<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:ec00730f-762b-46bc-8129-35ed9e118824,g:8015d53c-ba62-4fdf-81c5-b80d960aa246-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://simmonsbank.com/role/ConsolidatedStatementsofIncome" xlink:type="simple" xlink:href="sfnc-20210930.xsd#ConsolidatedStatementsofIncome"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/ConsolidatedStatementsofIncome" xlink:type="extended" id="if0c4ed36559342d98df070b8ccba166f_ConsolidatedStatementsofIncome">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestAndDividendIncomeOperatingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_56c0c4cb-5585-4df4-a8bc-18fe64295db2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:to="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_56c0c4cb-5585-4df4-a8bc-18fe64295db2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_79bbca86-12c1-4432-8d52-9d7d92eafbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_79bbca86-12c1-4432-8d52-9d7d92eafbb0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_9eac7b89-f593-47bb-be90-2c9914788c60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:to="loc_us-gaap_InvestmentIncomeInterest_9eac7b89-f593-47bb-be90-2c9914788c60" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestandFeeIncomeMortgageLoansHeldforsale_2afd1aba-2c10-4c3b-81d5-30b9a362cf3a" xlink:href="sfnc-20210930.xsd#sfnc_InterestandFeeIncomeMortgageLoansHeldforsale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:to="loc_sfnc_InterestandFeeIncomeMortgageLoansHeldforsale_2afd1aba-2c10-4c3b-81d5-30b9a362cf3a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_ce95cd28-dee3-4d76-b7d1-33fb397433c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_9edc7c2b-bbc7-4a61-bb8f-0e880e759914" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_ce95cd28-dee3-4d76-b7d1-33fb397433c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDeposits_04399c16-9f79-45b6-ac0c-55c691795c2a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:to="loc_us-gaap_InterestExpenseDeposits_04399c16-9f79-45b6-ac0c-55c691795c2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase_4bac3ce0-60d6-4725-a3c0-00a7942874a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:to="loc_us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase_4bac3ce0-60d6-4725-a3c0-00a7942874a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOther_36115883-3274-4ca3-9627-36fcb86ba0c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:to="loc_us-gaap_InterestExpenseOther_36115883-3274-4ca3-9627-36fcb86ba0c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_24ec422d-5141-4d47-bc86-d35ba43007a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_24ec422d-5141-4d47-bc86-d35ba43007a8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_fd5a3d3a-8ee6-4940-b1e6-040edd8fa222" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_ee33c38b-2e7e-45d5-bd22-df1fa2790a04" xlink:to="loc_us-gaap_InterestExpense_fd5a3d3a-8ee6-4940-b1e6-040edd8fa222" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_7f263d84-cad4-4edd-8011-34ef953d110a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_7f263d84-cad4-4edd-8011-34ef953d110a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_c84e605b-5439-4a38-a7c1-63405f93d07a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_c84e605b-5439-4a38-a7c1-63405f93d07a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_5cc5097f-5d94-4f90-9231-0d1b5242172c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_5cc5097f-5d94-4f90-9231-0d1b5242172c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoninterestIncomeAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_52214c2e-0ae7-4987-8b82-992860c3e612" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_52214c2e-0ae7-4987-8b82-992860c3e612" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentBankingRevenue_801db5f8-a937-4235-9cbb-faca9f7fd14e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentBankingRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_InvestmentBankingRevenue_801db5f8-a937-4235-9cbb-faca9f7fd14e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankOwnedLifeInsuranceIncome_3a608552-3be7-43f2-b009-08312e6e9db1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BankOwnedLifeInsuranceIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_BankOwnedLifeInsuranceIncome_3a608552-3be7-43f2-b009-08312e6e9db1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndEquitySecuritiesGainLoss_19e584e5-6a74-4c82-9f90-b2d10ab717a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_DebtAndEquitySecuritiesGainLoss_19e584e5-6a74-4c82-9f90-b2d10ab717a3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_0f95ca3a-774a-4830-b6bc-541da1a7e249" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_0f95ca3a-774a-4830-b6bc-541da1a7e249" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_de798c42-3bda-427b-9e54-0e3b9cf2ef69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoninterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_dcabb698-7ecd-4e48-b2dc-8e375cba99de" xlink:to="loc_us-gaap_NoninterestIncome_de798c42-3bda-427b-9e54-0e3b9cf2ef69" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoninterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_fb2170b4-c6fd-4880-9108-4b41fe7da63b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_LaborAndRelatedExpense_fb2170b4-c6fd-4880-9108-4b41fe7da63b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet_825117eb-2ea3-4bed-8d2a-dbd5723f7601" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OccupancyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_OccupancyNet_825117eb-2ea3-4bed-8d2a-dbd5723f7601" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentExpense_b04ad52e-3004-49f9-8b39-6fce11f41254" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquipmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_EquipmentExpense_b04ad52e-3004-49f9-8b39-6fce11f41254" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeclosedRealEstateExpense_02d86842-c948-424c-9663-26ce7ee4878a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeclosedRealEstateExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_ForeclosedRealEstateExpense_02d86842-c948-424c-9663-26ce7ee4878a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_4eea890c-fabb-4fcd-b017-5c612d7e5e07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalDepositInsuranceCorporationPremiumExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_4eea890c-fabb-4fcd-b017-5c612d7e5e07" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquisitionCosts_d8da6ca3-4659-4a88-9ed8-d72dee037f07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AcquisitionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_AcquisitionCosts_d8da6ca3-4659-4a88-9ed8-d72dee037f07" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoninterestExpense_d0600319-dd9f-4217-a178-dcf58d1c5988" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_OtherNoninterestExpense_d0600319-dd9f-4217-a178-dcf58d1c5988" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_ec6cecf0-6ede-49d3-a12a-d4e9f248bb1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_ed31de0d-9784-4bd3-8bf7-bc427d90bc27" xlink:to="loc_us-gaap_NoninterestExpense_ec6cecf0-6ede-49d3-a12a-d4e9f248bb1c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossAttributableToParent_1423edfe-7e4c-4284-ae97-2cf8654ddbd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_IncomeLossAttributableToParent_1423edfe-7e4c-4284-ae97-2cf8654ddbd1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_ba739b2c-948f-411b-b589-e850e4535ad2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_ba739b2c-948f-411b-b589-e850e4535ad2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_9702c3b5-13c8-4652-873e-881d0ef23b72" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_NetIncomeLoss_9702c3b5-13c8-4652-873e-881d0ef23b72" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_5c9ed424-cfb0-4b29-852f-5ade6915b3a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_5c9ed424-cfb0-4b29-852f-5ade6915b3a7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_b1506114-1952-4cb4-b5bf-7f7833b5ea9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_b1506114-1952-4cb4-b5bf-7f7833b5ea9b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_d05e0e81-b11e-4843-8253-f8284452a7ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_EarningsPerShareBasic_d05e0e81-b11e-4843-8253-f8284452a7ee" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_c5908436-e387-4aef-a8b5-d5cfe8827ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_EarningsPerShareDiluted_c5908436-e387-4aef-a8b5-d5cfe8827ff0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c3fcb1d7-12e8-49f0-b42e-c93205c96909" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ced34257-e96a-4bb4-84e4-8fd13607f103" xlink:to="loc_us-gaap_StatementTable_c3fcb1d7-12e8-49f0-b42e-c93205c96909" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c3fcb1d7-12e8-49f0-b42e-c93205c96909" xlink:to="loc_srt_ProductOrServiceAxis_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305" xlink:to="loc_srt_ProductsAndServicesDomain_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_a6a6bf0b-8e6f-46dd-b910-f8fef07ff305" xlink:to="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiduciaryAndTrustMember_5610a6f0-2ce9-4193-88ec-b88f5e014e98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiduciaryAndTrustMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_us-gaap_FiduciaryAndTrustMember_5610a6f0-2ce9-4193-88ec-b88f5e014e98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositAccountMember_5fc9743a-6ce6-43eb-9a0d-389f9937ef94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepositAccountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_us-gaap_DepositAccountMember_5fc9743a-6ce6-43eb-9a0d-389f9937ef94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialServiceOtherMember_b462c642-3a28-4d9e-9eec-4a5d54704f66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_us-gaap_FinancialServiceOtherMember_b462c642-3a28-4d9e-9eec-4a5d54704f66" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_MortgageLoansMember_1767215e-a88d-4d1e-b4b8-5302c4b9b2cc" xlink:href="sfnc-20210930.xsd#sfnc_MortgageLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_sfnc_MortgageLoansMember_1767215e-a88d-4d1e-b4b8-5302c4b9b2cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SBALoansMember_1f72fc4c-80ba-4c1f-8b64-a0d22920512d" xlink:href="sfnc-20210930.xsd#sfnc_SBALoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_sfnc_SBALoansMember_1f72fc4c-80ba-4c1f-8b64-a0d22920512d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditAndDebitCardMember_0c011b8a-ccd8-47bb-874c-d162309d2932" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditAndDebitCardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_42c9c9b3-1401-4422-9491-09f7e68ec83e" xlink:to="loc_us-gaap_CreditAndDebitCardMember_0c011b8a-ccd8-47bb-874c-d162309d2932" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="sfnc-20210930.xsd#ConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended" id="ic520c0caf2be4b40b7370e233f55a440_ConsolidatedStatementsofStockholdersEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_f884934d-4730-46db-97a4-b82c1966ed22" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_f884934d-4730-46db-97a4-b82c1966ed22" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_a88eb9db-5283-4f4e-8b09-1869fc656bdc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_StockholdersEquity_a88eb9db-5283-4f4e-8b09-1869fc656bdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_8200aea4-c84e-4b0e-8d9e-ebdda00958cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_8200aea4-c84e-4b0e-8d9e-ebdda00958cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_3cb53b5b-609d-4d5f-aab4-72ac63946f29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_3cb53b5b-609d-4d5f-aab4-72ac63946f29" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_4cbddf64-6064-4fff-af96-0be3631175eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_4cbddf64-6064-4fff-af96-0be3631175eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_c01acb66-c1ee-4efa-a001-fc6ed0593068" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_c01acb66-c1ee-4efa-a001-fc6ed0593068" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStock_e9ccc41b-a924-4989-b63c-1c65f138bb67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_DividendsPreferredStock_e9ccc41b-a924-4989-b63c-1c65f138bb67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_c69ad1eb-ec01-4cad-856f-42cd274367e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0172c735-53df-4fbf-9f5c-c3027470723d" xlink:to="loc_us-gaap_DividendsCommonStock_c69ad1eb-ec01-4cad-856f-42cd274367e9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_b69fd7f6-9250-431c-aa60-2acd3c0a4f76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdateExtensibleList_a6fe86e5-79b6-4447-a9b2-716faed85c07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdateExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_f884934d-4730-46db-97a4-b82c1966ed22" xlink:to="loc_us-gaap_AccountingStandardsUpdateExtensibleList_a6fe86e5-79b6-4447-a9b2-716faed85c07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_31f3820c-f3f2-4fe2-a968-e772fe962871" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_f884934d-4730-46db-97a4-b82c1966ed22" xlink:to="loc_us-gaap_StatementTable_31f3820c-f3f2-4fe2-a968-e772fe962871" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_000edcc0-b8da-4db2-a535-c9618c27bed5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_31f3820c-f3f2-4fe2-a968-e772fe962871" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_000edcc0-b8da-4db2-a535-c9618c27bed5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_000edcc0-b8da-4db2-a535-c9618c27bed5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_000edcc0-b8da-4db2-a535-c9618c27bed5" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_000edcc0-b8da-4db2-a535-c9618c27bed5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_202ecb5c-b78e-4ecf-a1db-e1c72713e707" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_000edcc0-b8da-4db2-a535-c9618c27bed5" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_202ecb5c-b78e-4ecf-a1db-e1c72713e707" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_604d3428-dff4-4348-952e-8be7420209ac" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_202ecb5c-b78e-4ecf-a1db-e1c72713e707" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_604d3428-dff4-4348-952e-8be7420209ac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_53adc635-3a68-48cc-a48c-b9e797489edd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_31f3820c-f3f2-4fe2-a968-e772fe962871" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_53adc635-3a68-48cc-a48c-b9e797489edd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_53adc635-3a68-48cc-a48c-b9e797489edd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_53adc635-3a68-48cc-a48c-b9e797489edd" xlink:to="loc_us-gaap_EquityComponentDomain_53adc635-3a68-48cc-a48c-b9e797489edd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_53adc635-3a68-48cc-a48c-b9e797489edd" xlink:to="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_cdb81e8f-0e4b-459e-a73d-340184941c29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:to="loc_us-gaap_PreferredStockMember_cdb81e8f-0e4b-459e-a73d-340184941c29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_c8e9bf13-48e8-42ed-bce7-516dee2fde84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:to="loc_us-gaap_CommonStockMember_c8e9bf13-48e8-42ed-bce7-516dee2fde84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_74079804-b204-4bd8-9e18-b2fa8625f2c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_74079804-b204-4bd8-9e18-b2fa8625f2c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_43c348b8-6393-4aa6-801a-5c040f0e2413" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_43c348b8-6393-4aa6-801a-5c040f0e2413" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_69ea5eb2-f94d-4f1d-8aef-047f63a40710" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_51528a6d-a996-4ace-a4d2-a7273ee89f69" xlink:to="loc_us-gaap_RetainedEarningsMember_69ea5eb2-f94d-4f1d-8aef-047f63a40710" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/PreparationofInterimFinancialStatementsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#PreparationofInterimFinancialStatementsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/PreparationofInterimFinancialStatementsDetails" xlink:type="extended" id="i368d00f2df1c4e3890d63f310ece0db7_PreparationofInterimFinancialStatementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_NumberOfFinancialCenters_2ad0725b-b1b4-45ae-a333-8fd53e4c1391" xlink:href="sfnc-20210930.xsd#sfnc_NumberOfFinancialCenters"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_sfnc_NumberOfFinancialCenters_2ad0725b-b1b4-45ae-a333-8fd53e4c1391" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_2ff6cbc3-982d-4469-9a28-5064bec81c78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_2ff6cbc3-982d-4469-9a28-5064bec81c78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiability_f450fafe-59f5-4122-8079-167e526ca4d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffBalanceSheetCreditLossLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiability_f450fafe-59f5-4122-8079-167e526ca4d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DebtSecuritiesAllowanceforCreditLoss_bf06a02a-d906-4d77-b6d1-080a5eeba15f" xlink:href="sfnc-20210930.xsd#sfnc_DebtSecuritiesAllowanceforCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_sfnc_DebtSecuritiesAllowanceforCreditLoss_bf06a02a-d906-4d77-b6d1-080a5eeba15f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_1905334b-e606-4223-94a3-4dc64e8a46d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_1905334b-e606-4223-94a3-4dc64e8a46d2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate_b96dc347-5d15-4923-ac3c-7e07aa7e157b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate_b96dc347-5d15-4923-ac3c-7e07aa7e157b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_cd377389-a527-4ba1-80b0-5852e1277b31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_30377c26-6c0a-4fe8-b16d-a81012c10c79" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_cd377389-a527-4ba1-80b0-5852e1277b31" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_769f700e-cb44-4cbb-bc3f-694cc847729d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_cd377389-a527-4ba1-80b0-5852e1277b31" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_769f700e-cb44-4cbb-bc3f-694cc847729d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_769f700e-cb44-4cbb-bc3f-694cc847729d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_769f700e-cb44-4cbb-bc3f-694cc847729d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_769f700e-cb44-4cbb-bc3f-694cc847729d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_e0d48a76-a4c5-45d1-be20-39936144f662" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_769f700e-cb44-4cbb-bc3f-694cc847729d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_e0d48a76-a4c5-45d1-be20-39936144f662" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_5a1c636e-1ff0-4056-9373-e12ad878fb10" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_e0d48a76-a4c5-45d1-be20-39936144f662" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_5a1c636e-1ff0-4056-9373-e12ad878fb10" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/AcquisitionsSubsequentEventTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#AcquisitionsSubsequentEventTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/AcquisitionsSubsequentEventTextualDetails" xlink:type="extended" id="i46e3fe61c7a04110a65fcfa8bdd19206_AcquisitionsSubsequentEventTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_b6f2fbe9-3411-4eb7-84f4-a4be9ee8fe7f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_b6f2fbe9-3411-4eb7-84f4-a4be9ee8fe7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_1b7d904c-aaa3-4a3a-b4b8-17148eed66e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_1b7d904c-aaa3-4a3a-b4b8-17148eed66e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BusinessCombinationNumberOfBankBranchesAcquired_ab5c9f1f-6c4f-4e1b-82b2-890c7a62f0d5" xlink:href="sfnc-20210930.xsd#sfnc_BusinessCombinationNumberOfBankBranchesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_sfnc_BusinessCombinationNumberOfBankBranchesAcquired_ab5c9f1f-6c4f-4e1b-82b2-890c7a62f0d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_fcbfacc7-fddd-4691-8023-2ceb46899668" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_fcbfacc7-fddd-4691-8023-2ceb46899668" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquiredReceivablesGrossContractualAmount_a49c55a8-146b-4825-ae4f-322958add92e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesGrossContractualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_us-gaap_BusinessCombinationAcquiredReceivablesGrossContractualAmount_a49c55a8-146b-4825-ae4f-322958add92e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesDeposits_d397e3f8-f8c4-4da8-8954-acc5e9c79006" xlink:href="sfnc-20210930.xsd#sfnc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_sfnc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesDeposits_d397e3f8-f8c4-4da8-8954-acc5e9c79006" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9fb7dc6-d826-4750-ba46-42d71758b86c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5672ded7-d02b-45c5-9d46-00f25017e069" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9fb7dc6-d826-4750-ba46-42d71758b86c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_e6410218-f45b-4de9-8fd8-157db67400a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9fb7dc6-d826-4750-ba46-42d71758b86c" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_e6410218-f45b-4de9-8fd8-157db67400a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e6410218-f45b-4de9-8fd8-157db67400a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e6410218-f45b-4de9-8fd8-157db67400a4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e6410218-f45b-4de9-8fd8-157db67400a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_38fce9d8-64fb-40e6-be2a-f45269293306" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e6410218-f45b-4de9-8fd8-157db67400a4" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_38fce9d8-64fb-40e6-be2a-f45269293306" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_LandmarkCommunityBankMember_f64d9209-4544-4869-abd3-dee884cf4663" xlink:href="sfnc-20210930.xsd#sfnc_LandmarkCommunityBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_38fce9d8-64fb-40e6-be2a-f45269293306" xlink:to="loc_sfnc_LandmarkCommunityBankMember_f64d9209-4544-4869-abd3-dee884cf4663" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TriumphBancsharesMember_a3bb0a12-1974-4475-997b-2db958a0e049" xlink:href="sfnc-20210930.xsd#sfnc_TriumphBancsharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_38fce9d8-64fb-40e6-be2a-f45269293306" xlink:to="loc_sfnc_TriumphBancsharesMember_a3bb0a12-1974-4475-997b-2db958a0e049" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesSummaryofInvestmentSecuritiesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesSummaryofInvestmentSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesSummaryofInvestmentSecuritiesDetails" xlink:type="extended" id="i5c952c0dd369466f80fc089e69cb8bb0_InvestmentSecuritiesSummaryofInvestmentSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d38ef5b4-1d1e-4744-8f2a-410d99461a23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d38ef5b4-1d1e-4744-8f2a-410d99461a23" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_8d34d179-582d-4142-80fc-e0f20c23eef7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_8d34d179-582d-4142-80fc-e0f20c23eef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_bf355663-a1cd-40e6-add7-36a4ad100333" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_bf355663-a1cd-40e6-add7-36a4ad100333" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_616a55de-e0dc-4563-a4ce-8c08db03c207" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_616a55de-e0dc-4563-a4ce-8c08db03c207" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_ee8cc707-231a-49fe-9599-a47ab0ed29ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_ee8cc707-231a-49fe-9599-a47ab0ed29ce" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_bc5546aa-7d03-4247-8117-7092ddabcd0f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_bc5546aa-7d03-4247-8117-7092ddabcd0f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_6a29a44c-2326-4dd2-b0ac-5b534f3475e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_e2e0aab1-e7d5-40c8-8bef-621a295b24e7" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_6a29a44c-2326-4dd2-b0ac-5b534f3475e6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d38ef5b4-1d1e-4744-8f2a-410d99461a23" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_07e7c53a-3dfb-4902-a3f0-0c04ea76ccd9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_07e7c53a-3dfb-4902-a3f0-0c04ea76ccd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_4790020c-69ef-44da-870b-7b8aeff0ddd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_4790020c-69ef-44da-870b-7b8aeff0ddd8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_47425ae7-2986-4bee-8047-706ce433ac47" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_47425ae7-2986-4bee-8047-706ce433ac47" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_44bf4b3d-c85a-4876-b753-2d68b63a770a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_44bf4b3d-c85a-4876-b753-2d68b63a770a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_bb0721bd-edd6-424b-85ff-13d8d5da9847" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_60bc927c-5ab6-4171-b8a0-8126539f6e5c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_bb0721bd-edd6-424b-85ff-13d8d5da9847" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_7ed81ea3-6fda-4033-8c34-3c70852d37c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d38ef5b4-1d1e-4744-8f2a-410d99461a23" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_7ed81ea3-6fda-4033-8c34-3c70852d37c1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_f795c1d3-667b-4aeb-9da2-ea25263d17f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_7ed81ea3-6fda-4033-8c34-3c70852d37c1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_f795c1d3-667b-4aeb-9da2-ea25263d17f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f795c1d3-667b-4aeb-9da2-ea25263d17f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f795c1d3-667b-4aeb-9da2-ea25263d17f1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f795c1d3-667b-4aeb-9da2-ea25263d17f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f795c1d3-667b-4aeb-9da2-ea25263d17f1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_5a476b15-71f0-4f19-9f53-8255abb0c899" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_5a476b15-71f0-4f19-9f53-8255abb0c899" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_c8dd3926-4bf5-42cb-a986-687a015d9c8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_c8dd3926-4bf5-42cb-a986-687a015d9c8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_cdbe5e06-248a-4f41-a3de-1db78d008f71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_cdbe5e06-248a-4f41-a3de-1db78d008f71" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_1cf9a2dc-8ab1-4a4f-9dbd-89585af8aac8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_1cf9a2dc-8ab1-4a4f-9dbd-89585af8aac8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_1df2bfcb-7e88-4f39-9b28-8761b0baf43d" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ac7f7001-71ef-42c9-ac76-33a3f74b310c" xlink:to="loc_sfnc_OtherSecuritiesMember_1df2bfcb-7e88-4f39-9b28-8761b0baf43d" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesTextualDetails" xlink:type="extended" id="i74768470f8e84290b7f4b7379a8566ea_InvestmentSecuritiesTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense_5d592dc8-b187-4e71-8c7f-fc4511dc6325" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense_5d592dc8-b187-4e71-8c7f-fc4511dc6325" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherComprehensiveIncomeUnrealizedGainsOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturity_e6cdc637-5081-48c2-b1ea-b6409fa6db33" xlink:href="sfnc-20210930.xsd#sfnc_OtherComprehensiveIncomeUnrealizedGainsOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_OtherComprehensiveIncomeUnrealizedGainsOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturity_e6cdc637-5081-48c2-b1ea-b6409fa6db33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityGainLoss_7138b5e6-23ef-498b-8f8e-cb4492c9fc04" xlink:href="sfnc-20210930.xsd#sfnc_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityGainLoss_7138b5e6-23ef-498b-8f8e-cb4492c9fc04" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_242d2abe-984d-40ac-9cb6-c315e222a8c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_242d2abe-984d-40ac-9cb6-c315e222a8c6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_97ecec09-017a-478b-b58a-25f3ea31d6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_97ecec09-017a-478b-b58a-25f3ea31d6ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DebtSecuritiesHeldtomaturityInterestReceivable_f3037b6b-5a8a-46e7-a291-89d4b38465c7" xlink:href="sfnc-20210930.xsd#sfnc_DebtSecuritiesHeldtomaturityInterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_DebtSecuritiesHeldtomaturityInterestReceivable_f3037b6b-5a8a-46e7-a291-89d4b38465c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DebtSecuritiesAvailableforsaleInterestReceivable_e401a2de-13d9-4f68-b6cb-480b9f541d33" xlink:href="sfnc-20210930.xsd#sfnc_DebtSecuritiesAvailableforsaleInterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_DebtSecuritiesAvailableforsaleInterestReceivable_e401a2de-13d9-4f68-b6cb-480b9f541d33" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_5e775507-123b-4f64-8fb3-4340553baf96" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_5e775507-123b-4f64-8fb3-4340553baf96" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_97e4b0a6-5715-4af5-a9dd-fdc5189303d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_97e4b0a6-5715-4af5-a9dd-fdc5189303d8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DebtSecuritiesUnrealizedLossPositionQuantitativeDisclosurePercent_fde33e69-e438-4266-ae44-397d9200dce4" xlink:href="sfnc-20210930.xsd#sfnc_DebtSecuritiesUnrealizedLossPositionQuantitativeDisclosurePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_DebtSecuritiesUnrealizedLossPositionQuantitativeDisclosurePercent_fde33e69-e438-4266-ae44-397d9200dce4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleChangeInPresentValueExpenseReversal_88ab6666-7878-456e-9c32-1e9ecebcfdd7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleChangeInPresentValueExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleChangeInPresentValueExpenseReversal_88ab6666-7878-456e-9c32-1e9ecebcfdd7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPeriodIncreaseDecrease_757dcdcf-7e74-4ff8-a418-e2f8e123bea6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPeriodIncreaseDecrease_757dcdcf-7e74-4ff8-a418-e2f8e123bea6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_40d1550d-467d-4665-895d-c9db543543e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_40d1550d-467d-4665-895d-c9db543543e2" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_1046035d-58df-4fe9-be99-4f29e01f0ded" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRestricted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_1046035d-58df-4fe9-be99-4f29e01f0ded" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_32be968a-bcb3-4524-86f3-9c978739bdb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_32be968a-bcb3-4524-86f3-9c978739bdb2" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss_d6b04809-3a69-4a9f-be9a-d658cb9f7b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss_d6b04809-3a69-4a9f-be9a-d658cb9f7b8d" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesSoldAtPar_076dc1a4-6fa4-42b4-bfb5-4c6180bd194e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableforsaleSecuritiesSoldAtPar"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesSoldAtPar_076dc1a4-6fa4-42b4-bfb5-4c6180bd194e" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_IncomeTaxBenefitRelatedToSecurityGainsLossesPercentage_05ac5127-cdee-418c-b29f-035d1fb05d48" xlink:href="sfnc-20210930.xsd#sfnc_IncomeTaxBenefitRelatedToSecurityGainsLossesPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_sfnc_IncomeTaxBenefitRelatedToSecurityGainsLossesPercentage_05ac5127-cdee-418c-b29f-035d1fb05d48" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_caf2f98e-45d4-474d-bfec-0d83d6ab3258" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_cae89285-578f-48b4-9fdc-db71bf75cd9c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_caf2f98e-45d4-474d-bfec-0d83d6ab3258" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_54bf331c-934a-4bd6-b4fa-87ab2d986c18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_caf2f98e-45d4-474d-bfec-0d83d6ab3258" xlink:to="loc_us-gaap_FinancialInstrumentAxis_54bf331c-934a-4bd6-b4fa-87ab2d986c18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_54bf331c-934a-4bd6-b4fa-87ab2d986c18_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_54bf331c-934a-4bd6-b4fa-87ab2d986c18" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_54bf331c-934a-4bd6-b4fa-87ab2d986c18_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_61d2301a-e8a1-4797-a6a8-a727e4e9bb04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_54bf331c-934a-4bd6-b4fa-87ab2d986c18" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_61d2301a-e8a1-4797-a6a8-a727e4e9bb04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_4e732271-5fee-4d4e-8aa5-fa7c67a7bf53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_61d2301a-e8a1-4797-a6a8-a727e4e9bb04" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_4e732271-5fee-4d4e-8aa5-fa7c67a7bf53" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_37a94343-0f42-418c-b92a-083c50ad754a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_61d2301a-e8a1-4797-a6a8-a727e4e9bb04" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_37a94343-0f42-418c-b92a-083c50ad754a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_f55eedd4-27cf-4854-ba60-ca643397ca11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_61d2301a-e8a1-4797-a6a8-a727e4e9bb04" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_f55eedd4-27cf-4854-ba60-ca643397ca11" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeAxis_92d9a4a6-fe61-40f8-abbf-c8241efd43a4" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_caf2f98e-45d4-474d-bfec-0d83d6ab3258" xlink:to="loc_sfnc_TypeofGuaranteeAxis_92d9a4a6-fe61-40f8-abbf-c8241efd43a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeDomain_92d9a4a6-fe61-40f8-abbf-c8241efd43a4_default" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_sfnc_TypeofGuaranteeAxis_92d9a4a6-fe61-40f8-abbf-c8241efd43a4" xlink:to="loc_sfnc_TypeofGuaranteeDomain_92d9a4a6-fe61-40f8-abbf-c8241efd43a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeDomain_74d6e08c-f1c6-4863-ba03-c4e9bfcf08a8" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_sfnc_TypeofGuaranteeAxis_92d9a4a6-fe61-40f8-abbf-c8241efd43a4" xlink:to="loc_sfnc_TypeofGuaranteeDomain_74d6e08c-f1c6-4863-ba03-c4e9bfcf08a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCreditEnhancementorInsuranceMember_9735a541-bf48-4652-8329-389d8cc2cf59" xlink:href="sfnc-20210930.xsd#sfnc_OtherCreditEnhancementorInsuranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_TypeofGuaranteeDomain_74d6e08c-f1c6-4863-ba03-c4e9bfcf08a8" xlink:to="loc_sfnc_OtherCreditEnhancementorInsuranceMember_9735a541-bf48-4652-8329-389d8cc2cf59" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesSecuritiesWithUnrealizedLossesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesSecuritiesWithUnrealizedLossesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesSecuritiesWithUnrealizedLossesDetails" xlink:type="extended" id="if3b3ad59b03e43c890a2c4016c5f0169_InvestmentSecuritiesSecuritiesWithUnrealizedLossesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_826d9c9a-3e65-4153-998a-eba11564ecdb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_826d9c9a-3e65-4153-998a-eba11564ecdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_b714d277-2290-49fa-b7e6-a6a7f135ca43" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_b714d277-2290-49fa-b7e6-a6a7f135ca43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_ef801bf8-47dd-4ccc-93d6-e53785da596e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_ef801bf8-47dd-4ccc-93d6-e53785da596e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_41e56e1b-b7a3-4ce2-800b-0401b5802ae0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_41e56e1b-b7a3-4ce2-800b-0401b5802ae0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_3b7987c9-c05c-43b0-aa96-ad2ec3a2b2f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_3b7987c9-c05c-43b0-aa96-ad2ec3a2b2f3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_3f450feb-0f08-40ea-b31c-0195d34c5bac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_3f450feb-0f08-40ea-b31c-0195d34c5bac" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_8cee67f1-f0da-45cf-9485-45ccd3d4d288" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_8daa309b-46ba-442e-8583-11fe43f9165d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_8cee67f1-f0da-45cf-9485-45ccd3d4d288" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_a0d628a6-7573-462e-8a7b-5e6472119622" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_8cee67f1-f0da-45cf-9485-45ccd3d4d288" xlink:to="loc_us-gaap_FinancialInstrumentAxis_a0d628a6-7573-462e-8a7b-5e6472119622" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a0d628a6-7573-462e-8a7b-5e6472119622_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a0d628a6-7573-462e-8a7b-5e6472119622" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a0d628a6-7573-462e-8a7b-5e6472119622_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a0d628a6-7573-462e-8a7b-5e6472119622" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_947a3459-afd0-463f-9761-c4146500b58c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_947a3459-afd0-463f-9761-c4146500b58c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_79624eb5-9940-4221-8291-e347ea8f483f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_79624eb5-9940-4221-8291-e347ea8f483f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_4fce7fcb-4206-45f6-881b-92e3cc11a588" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_4fce7fcb-4206-45f6-881b-92e3cc11a588" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_242dd69a-c615-42f9-8803-4d5df4d9aeba" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dafc53f9-bd9a-4333-8df5-8c0b2eda9369" xlink:to="loc_sfnc_OtherSecuritiesMember_242dd69a-c615-42f9-8803-4d5df4d9aeba" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesAllowanceforCreditLossesHTMDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesAllowanceforCreditLossesHTMDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesAllowanceforCreditLossesHTMDetails" xlink:type="extended" id="ic5e0856556f0479794015d91f437c330_InvestmentSecuritiesAllowanceforCreditLossesHTMDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_221d8a35-2bbd-436a-bfcc-33c12ee61fdd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_221d8a35-2bbd-436a-bfcc-33c12ee61fdd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditLossExpenseReversal_b161338f-09ff-4baa-8689-cac7d7b79ea6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditLossExpenseReversal_b161338f-09ff-4baa-8689-cac7d7b79ea6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff_52da3f12-e7fb-46b4-a153-b133ded490ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff_52da3f12-e7fb-46b4-a153-b133ded490ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery_2295913a-f7e4-4b20-a16b-99bd626603a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery_2295913a-f7e4-4b20-a16b-99bd626603a3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_4276793b-0798-49f3-b244-782bf4faf0d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_81d55d64-f865-49ac-9a09-aca2c89c3405" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_a784adf7-ff91-452b-9456-0498d07074e9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_81d55d64-f865-49ac-9a09-aca2c89c3405" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_81d55d64-f865-49ac-9a09-aca2c89c3405" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_9ff11dd4-4130-4bb8-bbf2-3e8bf786cd8e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_2158f5aa-80c4-4f4d-8a27-dc4c6ad91a98" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_9ff11dd4-4130-4bb8-bbf2-3e8bf786cd8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_8ed0b745-8195-4f5d-8bc1-9b68ea05cfbe" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_9ff11dd4-4130-4bb8-bbf2-3e8bf786cd8e" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_8ed0b745-8195-4f5d-8bc1-9b68ea05cfbe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_8ceefb45-686e-40a2-8c24-a87f43744f49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_81d55d64-f865-49ac-9a09-aca2c89c3405" xlink:to="loc_us-gaap_FinancialInstrumentAxis_8ceefb45-686e-40a2-8c24-a87f43744f49" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8ceefb45-686e-40a2-8c24-a87f43744f49_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_8ceefb45-686e-40a2-8c24-a87f43744f49" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8ceefb45-686e-40a2-8c24-a87f43744f49_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dd716378-af2c-4113-a071-2c644f1bbfa4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_8ceefb45-686e-40a2-8c24-a87f43744f49" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dd716378-af2c-4113-a071-2c644f1bbfa4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_65162554-cb65-4cd0-bf33-174f08d8c0e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dd716378-af2c-4113-a071-2c644f1bbfa4" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_65162554-cb65-4cd0-bf33-174f08d8c0e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_98ca7b67-54b2-477e-94c6-b0fec21c1656" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dd716378-af2c-4113-a071-2c644f1bbfa4" xlink:to="loc_sfnc_OtherSecuritiesMember_98ca7b67-54b2-477e-94c6-b0fec21c1656" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesAllowanceforCreditLossesAFSDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesAllowanceforCreditLossesAFSDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesAllowanceforCreditLossesAFSDetails" xlink:type="extended" id="i08a23c65be8b4bb7b50ad281ec75331a_InvestmentSecuritiesAllowanceforCreditLossesAFSDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableforsaleAllowanceForCreditLossLineItems_2ce3cb62-6763-42c6-8b36-51b0f2206c07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableforsaleAllowanceForCreditLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableforsaleAllowanceForCreditLossLineItems_2ce3cb62-6763-42c6-8b36-51b0f2206c07" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_bcc12a24-b4d7-4dd3-ba15-55ca3b55289f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_bcc12a24-b4d7-4dd3-ba15-55ca3b55289f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded_f8daf494-4b3d-4c51-8b80-f2a202f73463" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded_f8daf494-4b3d-4c51-8b80-f2a202f73463" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold_37cf0f1f-b0f4-48d8-b7ab-51e3f33fd712" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold_37cf0f1f-b0f4-48d8-b7ab-51e3f33fd712" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal_136e7626-8ec3-4615-8792-cb29f4b1dea5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bccd6e8e-4ce4-485d-85d9-eb373db08360" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal_136e7626-8ec3-4615-8792-cb29f4b1dea5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_437ee682-5856-46e6-9e8d-3c3d9bd32c55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTable_47fef3de-e1b7-4909-9b54-ac8fbc26942a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtSecuritiesAvailableforsaleAllowanceForCreditLossLineItems_2ce3cb62-6763-42c6-8b36-51b0f2206c07" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTable_47fef3de-e1b7-4909-9b54-ac8fbc26942a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_67067e0d-15f6-41db-a5d8-4d19684d7b2b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTable_47fef3de-e1b7-4909-9b54-ac8fbc26942a" xlink:to="loc_us-gaap_FinancialInstrumentAxis_67067e0d-15f6-41db-a5d8-4d19684d7b2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_67067e0d-15f6-41db-a5d8-4d19684d7b2b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_67067e0d-15f6-41db-a5d8-4d19684d7b2b" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_67067e0d-15f6-41db-a5d8-4d19684d7b2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8f2b56e1-aad9-4161-8f4c-0b98841ff1a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_67067e0d-15f6-41db-a5d8-4d19684d7b2b" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8f2b56e1-aad9-4161-8f4c-0b98841ff1a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_7eb14e6d-fb89-4176-889f-3493f0f3c4b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8f2b56e1-aad9-4161-8f4c-0b98841ff1a7" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_7eb14e6d-fb89-4176-889f-3493f0f3c4b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_3fe44aee-499d-488d-8e2e-78c9e2d00ef6" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8f2b56e1-aad9-4161-8f4c-0b98841ff1a7" xlink:to="loc_sfnc_OtherSecuritiesMember_3fe44aee-499d-488d-8e2e-78c9e2d00ef6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTable_47fef3de-e1b7-4909-9b54-ac8fbc26942a" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7d688f1a-abf0-4c41-b9d3-700a8d959d32" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_8ede4e4a-7cb8-489c-8d5f-5b40bc699fe1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7d688f1a-abf0-4c41-b9d3-700a8d959d32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_3c8e7d6e-9aa4-4529-9289-4064d29addbb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7d688f1a-abf0-4c41-b9d3-700a8d959d32" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_3c8e7d6e-9aa4-4529-9289-4064d29addbb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesCreditQualityIndicatorDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesCreditQualityIndicatorDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesCreditQualityIndicatorDetails" xlink:type="extended" id="i2f3dc10d139f40aea8dcbd7a22a02e51_InvestmentSecuritiesCreditQualityIndicatorDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_6b7969e0-6da3-4eb1-b5da-98486e979c29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_68dd19e1-42f1-4e70-b480-294bbf4dd764" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_6b7969e0-6da3-4eb1-b5da-98486e979c29" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_68dd19e1-42f1-4e70-b480-294bbf4dd764" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_9bad1618-36f8-48d5-8eb6-123342a0efed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_6b7969e0-6da3-4eb1-b5da-98486e979c29" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_9bad1618-36f8-48d5-8eb6-123342a0efed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeAxis_93d34cd0-02bf-4bad-9310-21f72b1f201c" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_9bad1618-36f8-48d5-8eb6-123342a0efed" xlink:to="loc_sfnc_TypeofGuaranteeAxis_93d34cd0-02bf-4bad-9310-21f72b1f201c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeDomain_93d34cd0-02bf-4bad-9310-21f72b1f201c_default" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_sfnc_TypeofGuaranteeAxis_93d34cd0-02bf-4bad-9310-21f72b1f201c" xlink:to="loc_sfnc_TypeofGuaranteeDomain_93d34cd0-02bf-4bad-9310-21f72b1f201c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TypeofGuaranteeDomain_f123b348-ae96-4583-b704-dc50dc389b69" xlink:href="sfnc-20210930.xsd#sfnc_TypeofGuaranteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_sfnc_TypeofGuaranteeAxis_93d34cd0-02bf-4bad-9310-21f72b1f201c" xlink:to="loc_sfnc_TypeofGuaranteeDomain_f123b348-ae96-4583-b704-dc50dc389b69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_NotGuaranteedorPreRefundedMember_8647ff0f-85f3-4c78-8b12-75ba665fa405" xlink:href="sfnc-20210930.xsd#sfnc_NotGuaranteedorPreRefundedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_TypeofGuaranteeDomain_f123b348-ae96-4583-b704-dc50dc389b69" xlink:to="loc_sfnc_NotGuaranteedorPreRefundedMember_8647ff0f-85f3-4c78-8b12-75ba665fa405" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCreditEnhancementorInsuranceMember_f919dddf-714e-4333-9bd7-63330de7c339" xlink:href="sfnc-20210930.xsd#sfnc_OtherCreditEnhancementorInsuranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_TypeofGuaranteeDomain_f123b348-ae96-4583-b704-dc50dc389b69" xlink:to="loc_sfnc_OtherCreditEnhancementorInsuranceMember_f919dddf-714e-4333-9bd7-63330de7c339" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_PreRefundedMember_cd2be9ad-f94e-4e1c-a1fa-eec14af740b3" xlink:href="sfnc-20210930.xsd#sfnc_PreRefundedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_TypeofGuaranteeDomain_f123b348-ae96-4583-b704-dc50dc389b69" xlink:to="loc_sfnc_PreRefundedMember_cd2be9ad-f94e-4e1c-a1fa-eec14af740b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CreditRatingBondAxis_7bbd094b-be84-4413-8608-d48085c56293" xlink:href="sfnc-20210930.xsd#sfnc_CreditRatingBondAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_9bad1618-36f8-48d5-8eb6-123342a0efed" xlink:to="loc_sfnc_CreditRatingBondAxis_7bbd094b-be84-4413-8608-d48085c56293" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CreditRatingBondDomain_7bbd094b-be84-4413-8608-d48085c56293_default" xlink:href="sfnc-20210930.xsd#sfnc_CreditRatingBondDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_sfnc_CreditRatingBondAxis_7bbd094b-be84-4413-8608-d48085c56293" xlink:to="loc_sfnc_CreditRatingBondDomain_7bbd094b-be84-4413-8608-d48085c56293_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:href="sfnc-20210930.xsd#sfnc_CreditRatingBondDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_sfnc_CreditRatingBondAxis_7bbd094b-be84-4413-8608-d48085c56293" xlink:to="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BondAaaAAARatingMember_23d25be0-e4c2-40a2-a42b-ce842408fda4" xlink:href="sfnc-20210930.xsd#sfnc_BondAaaAAARatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:to="loc_sfnc_BondAaaAAARatingMember_23d25be0-e4c2-40a2-a42b-ce842408fda4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BondAaAARatingMember_4cd82a09-5f07-4185-8d25-7bd621bd0a4c" xlink:href="sfnc-20210930.xsd#sfnc_BondAaAARatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:to="loc_sfnc_BondAaAARatingMember_4cd82a09-5f07-4185-8d25-7bd621bd0a4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BondARatingMember_c7a0e5dd-8a18-4f08-bbb8-aad6fa778b25" xlink:href="sfnc-20210930.xsd#sfnc_BondARatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:to="loc_sfnc_BondARatingMember_c7a0e5dd-8a18-4f08-bbb8-aad6fa778b25" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BondBaaBBBRatingMember_f132a5ec-5e6b-4ddf-81ec-bdfadef7c689" xlink:href="sfnc-20210930.xsd#sfnc_BondBaaBBBRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:to="loc_sfnc_BondBaaBBBRatingMember_f132a5ec-5e6b-4ddf-81ec-bdfadef7c689" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BondNotRatedMember_dc89062c-9a7c-4c1e-8549-1aa187ee3591" xlink:href="sfnc-20210930.xsd#sfnc_BondNotRatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_CreditRatingBondDomain_0e431bf4-c559-419f-84e5-a5b823b1d70f" xlink:to="loc_sfnc_BondNotRatedMember_dc89062c-9a7c-4c1e-8549-1aa187ee3591" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_642904f2-023f-4305-ad39-512df9d68179" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_9bad1618-36f8-48d5-8eb6-123342a0efed" xlink:to="loc_us-gaap_FinancialInstrumentAxis_642904f2-023f-4305-ad39-512df9d68179" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_642904f2-023f-4305-ad39-512df9d68179_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_642904f2-023f-4305-ad39-512df9d68179" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_642904f2-023f-4305-ad39-512df9d68179_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f2dd45c-4169-4e4e-bc48-f13ab99a0d4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_642904f2-023f-4305-ad39-512df9d68179" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f2dd45c-4169-4e4e-bc48-f13ab99a0d4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_47ef3473-76d3-44c7-a85f-5bc5338752ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f2dd45c-4169-4e4e-bc48-f13ab99a0d4c" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_47ef3473-76d3-44c7-a85f-5bc5338752ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_f5f79579-110c-4a89-aa71-74b638820b64" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f2dd45c-4169-4e4e-bc48-f13ab99a0d4c" xlink:to="loc_sfnc_OtherSecuritiesMember_f5f79579-110c-4a89-aa71-74b638820b64" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/InvestmentSecuritiesIncomeEarnedonSecuritiesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#InvestmentSecuritiesIncomeEarnedonSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/InvestmentSecuritiesIncomeEarnedonSecuritiesDetails" xlink:type="extended" id="ic2308d4bef454a76b572aa61154e1f02_InvestmentSecuritiesIncomeEarnedonSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_32621e03-69c1-4b93-a4c6-0a69280cfda1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesOperatingByTaxableStatusAbstract_ef66a03b-a110-4e94-aa38-32dd874f6fec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeSecuritiesOperatingByTaxableStatusAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_32621e03-69c1-4b93-a4c6-0a69280cfda1" xlink:to="loc_us-gaap_InterestIncomeSecuritiesOperatingByTaxableStatusAbstract_ef66a03b-a110-4e94-aa38-32dd874f6fec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxable_ce4d9eb3-eab0-4177-91a9-da29a88e36c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestIncomeSecuritiesOperatingByTaxableStatusAbstract_ef66a03b-a110-4e94-aa38-32dd874f6fec" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxable_ce4d9eb3-eab0-4177-91a9-da29a88e36c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestIncomeSecuritiesOperatingByNonTaxableStatusAbstract_8c9d70e4-9f55-46dc-a36a-171625d85c78" xlink:href="sfnc-20210930.xsd#sfnc_InterestIncomeSecuritiesOperatingByNonTaxableStatusAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_32621e03-69c1-4b93-a4c6-0a69280cfda1" xlink:to="loc_sfnc_InterestIncomeSecuritiesOperatingByNonTaxableStatusAbstract_8c9d70e4-9f55-46dc-a36a-171625d85c78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_759af702-68d5-45f5-90b3-86b55c9d8b56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sfnc_InterestIncomeSecuritiesOperatingByNonTaxableStatusAbstract_8c9d70e4-9f55-46dc-a36a-171625d85c78" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_759af702-68d5-45f5-90b3-86b55c9d8b56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_84c3ef22-7a0b-4693-9d57-01cc664dacf9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_32621e03-69c1-4b93-a4c6-0a69280cfda1" xlink:to="loc_us-gaap_InvestmentIncomeInterest_84c3ef22-7a0b-4693-9d57-01cc664dacf9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_d9d6e38a-46fc-459f-a07e-0538f60ee913" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_32621e03-69c1-4b93-a4c6-0a69280cfda1" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_d9d6e38a-46fc-459f-a07e-0538f60ee913" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_7447b658-3a44-4013-8c68-3262f90f6fb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InformationByCategoryOfDebtSecurityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_d9d6e38a-46fc-459f-a07e-0538f60ee913" xlink:to="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_7447b658-3a44-4013-8c68-3262f90f6fb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_7447b658-3a44-4013-8c68-3262f90f6fb0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_7447b658-3a44-4013-8c68-3262f90f6fb0" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_7447b658-3a44-4013-8c68-3262f90f6fb0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_54075b08-d77a-4953-93f6-0f5195e84bd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_7447b658-3a44-4013-8c68-3262f90f6fb0" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_54075b08-d77a-4953-93f6-0f5195e84bd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesMember_eb67badf-7ada-4d3f-9e2a-280496b7a3ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldtomaturitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_54075b08-d77a-4953-93f6-0f5195e84bd0" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesMember_eb67badf-7ada-4d3f-9e2a-280496b7a3ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember_cd2b18f6-267c-49b2-8ce6-3f93dddf0d91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_54075b08-d77a-4953-93f6-0f5195e84bd0" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesMember_cd2b18f6-267c-49b2-8ce6-3f93dddf0d91" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/OtherLiabilitiesHeldforSaleDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#OtherLiabilitiesHeldforSaleDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/OtherLiabilitiesHeldforSaleDetails" xlink:type="extended" id="i4c858a7a21804c8da6129a204d89704b_OtherLiabilitiesHeldforSaleDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_NumberOfBranchesSold_76f21031-d463-4f54-96d9-6e51cd47145b" xlink:href="sfnc-20210930.xsd#sfnc_NumberOfBranchesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_sfnc_NumberOfBranchesSold_76f21031-d463-4f54-96d9-6e51cd47145b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleAmount_986c3cf9-c615-4b6b-a347-49961449691c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansReceivableHeldForSaleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleAmount_986c3cf9-c615-4b6b-a347-49961449691c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DepositLiabilitiesHeldForSale_f3e11ac2-3893-4f4e-a299-1f0c8b116c8a" xlink:href="sfnc-20210930.xsd#sfnc_DepositLiabilitiesHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_sfnc_DepositLiabilitiesHeldForSale_f3e11ac2-3893-4f4e-a299-1f0c8b116c8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_8a405e40-0e0a-46b9-8577-0767e6c26b97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_8a405e40-0e0a-46b9-8577-0767e6c26b97" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherLiabilities_866be746-6a30-4484-81e6-41081cf64138" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherLiabilities_866be746-6a30-4484-81e6-41081cf64138" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77909f61-518f-4576-9022-730d080fa51e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e03e86b0-d90a-4b9d-a790-a0433ee30692" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77909f61-518f-4576-9022-730d080fa51e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_344f36d1-d0a4-4dc4-94f3-033cc2263b07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77909f61-518f-4576-9022-730d080fa51e" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_344f36d1-d0a4-4dc4-94f3-033cc2263b07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_344f36d1-d0a4-4dc4-94f3-033cc2263b07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_344f36d1-d0a4-4dc4-94f3-033cc2263b07" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_344f36d1-d0a4-4dc4-94f3-033cc2263b07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_ce80a158-884f-406a-be9c-0f1db832b4d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_344f36d1-d0a4-4dc4-94f3-033cc2263b07" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_ce80a158-884f-406a-be9c-0f1db832b4d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_a7393c4a-4274-494a-aad3-aaaf210f85ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_ce80a158-884f-406a-be9c-0f1db832b4d3" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_a7393c4a-4274-494a-aad3-aaaf210f85ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0dd02958-adef-448f-bcab-454b6f86af89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77909f61-518f-4576-9022-730d080fa51e" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0dd02958-adef-448f-bcab-454b6f86af89" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0dd02958-adef-448f-bcab-454b6f86af89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0dd02958-adef-448f-bcab-454b6f86af89" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0dd02958-adef-448f-bcab-454b6f86af89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_80e12994-cd30-4fdd-90f2-9c46098ae4ad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0dd02958-adef-448f-bcab-454b6f86af89" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_80e12994-cd30-4fdd-90f2-9c46098ae4ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_IllinoisBranchesMember_165410e9-c118-4e98-9d2a-b94a4b1097cf" xlink:href="sfnc-20210930.xsd#sfnc_IllinoisBranchesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_80e12994-cd30-4fdd-90f2-9c46098ae4ad" xlink:to="loc_sfnc_IllinoisBranchesMember_165410e9-c118-4e98-9d2a-b94a4b1097cf" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesTextualDetails" xlink:type="extended" id="idebe9961ddde4de6b079b08b73c27707_LoansandAllowanceforCreditLossesTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_a54dc34b-bf91-4f04-8475-29ae2692064d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_a54dc34b-bf91-4f04-8475-29ae2692064d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePurchasedWithCreditDeteriorationDiscountPremium_5e8904c8-efc0-4b54-8448-d67672f7d64f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePurchasedWithCreditDeteriorationDiscountPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivablePurchasedWithCreditDeteriorationDiscountPremium_5e8904c8-efc0-4b54-8448-d67672f7d64f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAccruedInterestBeforeAllowanceForCreditLoss_4cfcf3b0-256d-45ba-ba51-78774a7e6546" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableAccruedInterestBeforeAllowanceForCreditLoss_4cfcf3b0-256d-45ba-ba51-78774a7e6546" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancingReceivableTermOfLoan_eca58b5a-a6db-43ad-9bd6-0747af2fcdac" xlink:href="sfnc-20210930.xsd#sfnc_FinancingReceivableTermOfLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_sfnc_FinancingReceivableTermOfLoan_eca58b5a-a6db-43ad-9bd6-0747af2fcdac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualNoAllowance_1fa58c66-05a4-45fa-ae7d-f353f8a2dfec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualNoAllowance_1fa58c66-05a4-45fa-ae7d-f353f8a2dfec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_e76a688e-054b-42fa-b8f4-812ba47d3be8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_e76a688e-054b-42fa-b8f4-812ba47d3be8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_ee05b058-2a6c-43d6-b3e1-7146ad144f47" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_ee05b058-2a6c-43d6-b3e1-7146ad144f47" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_15974160-3d31-4184-90f6-8a94f4efcf67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_15974160-3d31-4184-90f6-8a94f4efcf67" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_f2df405e-380d-434a-9e20-9d3132769f74" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_f2df405e-380d-434a-9e20-9d3132769f74" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_e12e6ff4-255d-4972-a97b-b3e5ede5c9e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_e12e6ff4-255d-4972-a97b-b3e5ede5c9e2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansInProcessOfForeclosureAmount_5f9071d1-b1cc-475a-94a5-a313e95f15a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansInProcessOfForeclosureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_MortgageLoansInProcessOfForeclosureAmount_5f9071d1-b1cc-475a-94a5-a313e95f15a0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAcquiredThroughForeclosure_0f189532-14c4-4bd7-9207-898639e02732" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAcquiredThroughForeclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_RealEstateAcquiredThroughForeclosure_0f189532-14c4-4bd7-9207-898639e02732" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancingReceivableCollateralDependentAmount_3e4b8442-7669-4577-8c12-483ac851623b" xlink:href="sfnc-20210930.xsd#sfnc_FinancingReceivableCollateralDependentAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_sfnc_FinancingReceivableCollateralDependentAmount_3e4b8442-7669-4577-8c12-483ac851623b" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_NumberOfEnergyCredits_375cd0fc-8095-465f-8b16-68a75b98c121" xlink:href="sfnc-20210930.xsd#sfnc_NumberOfEnergyCredits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_sfnc_NumberOfEnergyCredits_375cd0fc-8095-465f-8b16-68a75b98c121" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_d3142b89-e60b-4c61-ac0a-9ca350eeff7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_d3142b89-e60b-4c61-ac0a-9ca350eeff7c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiability_0c472722-ce56-4027-ba6f-bdf01e651fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffBalanceSheetCreditLossLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiability_0c472722-ce56-4027-ba6f-bdf01e651fa8" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_2b762935-d494-4879-998d-fe45725ac639" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_2b762935-d494-4879-998d-fe45725ac639" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_2b5f6bc3-45ac-491c-a79b-51d3da3d7b48" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_a2b3b82c-99f2-4c6d-bb75-b24513edea9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_a2b3b82c-99f2-4c6d-bb75-b24513edea9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_a2b3b82c-99f2-4c6d-bb75-b24513edea9c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_a2b3b82c-99f2-4c6d-bb75-b24513edea9c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_a2b3b82c-99f2-4c6d-bb75-b24513edea9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_a2b3b82c-99f2-4c6d-bb75-b24513edea9c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_e04bfc27-9f7a-478f-968c-ad8b92e86db3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:to="loc_srt_SingleFamilyMember_e04bfc27-9f7a-478f-968c-ad8b92e86db3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_4484cbe0-5ddf-4efd-90ba-049167dea1f8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:to="loc_us-gaap_CommercialRealEstateMember_4484cbe0-5ddf-4efd-90ba-049167dea1f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_285f2f75-c8a2-43d1-9482-a489f70c1dce" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:to="loc_sfnc_OtherCommercialLoansMember_285f2f75-c8a2-43d1-9482-a489f70c1dce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_PaycheckProtectionProgramLoansMember_87a9e164-d7d1-4006-89f2-fca81688d05a" xlink:href="sfnc-20210930.xsd#sfnc_PaycheckProtectionProgramLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_022e1b39-277f-494c-a714-d6fbde93ae1f" xlink:to="loc_sfnc_PaycheckProtectionProgramLoansMember_87a9e164-d7d1-4006-89f2-fca81688d05a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f586bcc-6164-4956-a8a7-e24313d55abb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5a1896f1-1a7e-4f2f-b8ac-4b54649d240e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f586bcc-6164-4956-a8a7-e24313d55abb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_6ce9f761-6893-40a7-9c47-5dba360d9212" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f586bcc-6164-4956-a8a7-e24313d55abb" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_6ce9f761-6893-40a7-9c47-5dba360d9212" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_b7fd46c2-621c-4dcc-89ee-293c72717776" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_b7fd46c2-621c-4dcc-89ee-293c72717776" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_b7fd46c2-621c-4dcc-89ee-293c72717776_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_b7fd46c2-621c-4dcc-89ee-293c72717776" xlink:to="loc_us-gaap_ReceivableTypeDomain_b7fd46c2-621c-4dcc-89ee-293c72717776_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_353b941f-2aef-46aa-a3f0-3fccccf93c1e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_b7fd46c2-621c-4dcc-89ee-293c72717776" xlink:to="loc_us-gaap_ReceivableTypeDomain_353b941f-2aef-46aa-a3f0-3fccccf93c1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAcquiredInSatisfactionOfDebtMember_4865565b-4c69-4cb2-a9d3-b63577b92ffe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateAcquiredInSatisfactionOfDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_353b941f-2aef-46aa-a3f0-3fccccf93c1e" xlink:to="loc_us-gaap_RealEstateAcquiredInSatisfactionOfDebtMember_4865565b-4c69-4cb2-a9d3-b63577b92ffe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_a829722a-a0b3-4f90-8042-4506ccde4d22" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_CollateralAxis_a829722a-a0b3-4f90-8042-4506ccde4d22" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_a829722a-a0b3-4f90-8042-4506ccde4d22_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_a829722a-a0b3-4f90-8042-4506ccde4d22" xlink:to="loc_us-gaap_CollateralDomain_a829722a-a0b3-4f90-8042-4506ccde4d22_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_d52c74da-ded5-4ba1-a86e-1a3fdae3eaf3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_a829722a-a0b3-4f90-8042-4506ccde4d22" xlink:to="loc_us-gaap_CollateralDomain_d52c74da-ded5-4ba1-a86e-1a3fdae3eaf3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_9cebbacb-2aab-4a10-83ae-b3f85c0718c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_d52c74da-ded5-4ba1-a86e-1a3fdae3eaf3" xlink:to="loc_us-gaap_ResidentialRealEstateMember_9cebbacb-2aab-4a10-83ae-b3f85c0718c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SecuredEnergyProductionAssetsMember_eb71d485-65fb-40cf-8eff-2e13887f4743" xlink:href="sfnc-20210930.xsd#sfnc_SecuredEnergyProductionAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_d52c74da-ded5-4ba1-a86e-1a3fdae3eaf3" xlink:to="loc_sfnc_SecuredEnergyProductionAssetsMember_eb71d485-65fb-40cf-8eff-2e13887f4743" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_1f243b36-adb8-49f7-a3c4-658864a4ebc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_1f243b36-adb8-49f7-a3c4-658864a4ebc2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_1f243b36-adb8-49f7-a3c4-658864a4ebc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_1f243b36-adb8-49f7-a3c4-658864a4ebc2" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_1f243b36-adb8-49f7-a3c4-658864a4ebc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_1bf3730b-4647-4c36-932a-84ca89b2a24b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_1f243b36-adb8-49f7-a3c4-658864a4ebc2" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_1bf3730b-4647-4c36-932a-84ca89b2a24b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_ExtendedMaturityandPaymentDeferralMember_8929c1ee-a5ba-45ce-afb0-6ba4027b3499" xlink:href="sfnc-20210930.xsd#sfnc_ExtendedMaturityandPaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_1bf3730b-4647-4c36-932a-84ca89b2a24b" xlink:to="loc_sfnc_ExtendedMaturityandPaymentDeferralMember_8929c1ee-a5ba-45ce-afb0-6ba4027b3499" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_651619b2-8524-4da5-a753-46ca897fdd67" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_651619b2-8524-4da5-a753-46ca897fdd67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_651619b2-8524-4da5-a753-46ca897fdd67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_651619b2-8524-4da5-a753-46ca897fdd67" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_651619b2-8524-4da5-a753-46ca897fdd67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_e6420377-80f6-4440-8bd1-7f9b32e5a9bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_651619b2-8524-4da5-a753-46ca897fdd67" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_e6420377-80f6-4440-8bd1-7f9b32e5a9bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_COVID19PandemicMember_0f116738-91ab-448b-b5b1-b08732f11505" xlink:href="sfnc-20210930.xsd#sfnc_COVID19PandemicMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_e6420377-80f6-4440-8bd1-7f9b32e5a9bf" xlink:to="loc_sfnc_COVID19PandemicMember_0f116738-91ab-448b-b5b1-b08732f11505" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bb5ec120-6469-41fe-8ca0-1be88bd87f21" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_e409570e-cea6-4d86-af81-6ea2e5ece773" xlink:to="loc_srt_RangeAxis_bb5ec120-6469-41fe-8ca0-1be88bd87f21" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bb5ec120-6469-41fe-8ca0-1be88bd87f21_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bb5ec120-6469-41fe-8ca0-1be88bd87f21" xlink:to="loc_srt_RangeMember_bb5ec120-6469-41fe-8ca0-1be88bd87f21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_625ae6d4-5991-4975-a1ac-a4ed534d49c7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bb5ec120-6469-41fe-8ca0-1be88bd87f21" xlink:to="loc_srt_RangeMember_625ae6d4-5991-4975-a1ac-a4ed534d49c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_a455dcf0-902a-4458-83e5-c0358e06ae37" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_625ae6d4-5991-4975-a1ac-a4ed534d49c7" xlink:to="loc_srt_MinimumMember_a455dcf0-902a-4458-83e5-c0358e06ae37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_98c67fb3-1399-4cad-ac98-a69ed4216818" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_625ae6d4-5991-4975-a1ac-a4ed534d49c7" xlink:to="loc_srt_MaximumMember_98c67fb3-1399-4cad-ac98-a69ed4216818" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoanPortfoliobyCategoriesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesLoanPortfoliobyCategoriesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoanPortfoliobyCategoriesDetails" xlink:type="extended" id="i440a4f42a92d49dbb8b97cb539160b5c_LoansandAllowanceforCreditLossesLoanPortfoliobyCategoriesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_4525f5a0-fabc-4001-837c-3520da12d4b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_9a8d6de7-1701-4c50-83d4-0ff9a558172e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_4525f5a0-fabc-4001-837c-3520da12d4b6" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_9a8d6de7-1701-4c50-83d4-0ff9a558172e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_a127ccf0-cc7c-4249-a8d7-3e963586db77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_4525f5a0-fabc-4001-837c-3520da12d4b6" xlink:to="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_a127ccf0-cc7c-4249-a8d7-3e963586db77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_033c7183-4cc9-4408-a37c-2fa22cf2e402" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_a127ccf0-cc7c-4249-a8d7-3e963586db77" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_033c7183-4cc9-4408-a37c-2fa22cf2e402" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_033c7183-4cc9-4408-a37c-2fa22cf2e402_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_033c7183-4cc9-4408-a37c-2fa22cf2e402" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_033c7183-4cc9-4408-a37c-2fa22cf2e402_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_033c7183-4cc9-4408-a37c-2fa22cf2e402" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_51247b75-2b4d-4d26-9586-ef395abec35f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_51247b75-2b4d-4d26-9586-ef395abec35f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_b89df3b4-ef95-4fec-bf3b-8d14ded1c8d9" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_b89df3b4-ef95-4fec-bf3b-8d14ded1c8d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_676d1f53-a20a-496c-b384-2395c69c06c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_676d1f53-a20a-496c-b384-2395c69c06c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnallocatedFinancingReceivablesMember_cce812b9-eda8-445b-9bb2-1d28c50cb9b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnallocatedFinancingReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71c29212-788f-490f-be80-537bdd7e6b11" xlink:to="loc_us-gaap_UnallocatedFinancingReceivablesMember_cce812b9-eda8-445b-9bb2-1d28c50cb9b3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_deb13481-ed4f-407a-ab74-b318e9d3bce2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_a127ccf0-cc7c-4249-a8d7-3e963586db77" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_deb13481-ed4f-407a-ab74-b318e9d3bce2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_deb13481-ed4f-407a-ab74-b318e9d3bce2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_deb13481-ed4f-407a-ab74-b318e9d3bce2" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_deb13481-ed4f-407a-ab74-b318e9d3bce2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_deb13481-ed4f-407a-ab74-b318e9d3bce2" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_570a6b5b-1589-4f0e-a64d-31643b4793c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_us-gaap_CreditCardReceivablesMember_570a6b5b-1589-4f0e-a64d-31643b4793c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherConsumerLoansMember_fc4395ab-158f-42f5-a7f4-4498ce7d9f45" xlink:href="sfnc-20210930.xsd#sfnc_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_sfnc_OtherConsumerLoansMember_fc4395ab-158f-42f5-a7f4-4498ce7d9f45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_ea53f6e3-bdd3-4c43-8829-4585a64b6842" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_us-gaap_ConstructionLoansMember_ea53f6e3-bdd3-4c43-8829-4585a64b6842" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_6a8dfc3f-2afe-4d27-a8d9-600f96b4ea06" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_srt_SingleFamilyMember_6a8dfc3f-2afe-4d27-a8d9-600f96b4ea06" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_11eeea4f-5923-491c-8393-69ba909ab4a1" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_sfnc_OtherCommercialLoansMember_11eeea4f-5923-491c-8393-69ba909ab4a1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_83285824-9974-415d-a57d-45208a73878c" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_sfnc_CommercialLoansMember_83285824-9974-415d-a57d-45208a73878c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_AgriculturalLoansMember_ea610a74-cb99-497d-ae9a-edff92552891" xlink:href="sfnc-20210930.xsd#sfnc_AgriculturalLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_fae69b87-9f0b-4957-a177-fdb9be448b82" xlink:to="loc_sfnc_AgriculturalLoansMember_ea610a74-cb99-497d-ae9a-edff92552891" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesNonaccrualLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesNonaccrualLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesNonaccrualLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="extended" id="i6912c8f5dc1a4a30bdf4bc4178821f15_LoansandAllowanceforCreditLossesNonaccrualLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_217d482c-ddf7-4d64-bb63-1301001cb112" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_3ae35157-5a9a-4763-a67c-abc94c5d5223" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_217d482c-ddf7-4d64-bb63-1301001cb112" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_3ae35157-5a9a-4763-a67c-abc94c5d5223" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_8bc2f133-0ae2-4c60-adbe-a630f2b3f39a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_217d482c-ddf7-4d64-bb63-1301001cb112" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_8bc2f133-0ae2-4c60-adbe-a630f2b3f39a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_ef65de2d-86ee-494d-b9a6-b5456a7a72a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_8bc2f133-0ae2-4c60-adbe-a630f2b3f39a" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_ef65de2d-86ee-494d-b9a6-b5456a7a72a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ef65de2d-86ee-494d-b9a6-b5456a7a72a3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_ef65de2d-86ee-494d-b9a6-b5456a7a72a3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ef65de2d-86ee-494d-b9a6-b5456a7a72a3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d10a571-b51b-47a0-99a7-7279b31ff6bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_ef65de2d-86ee-494d-b9a6-b5456a7a72a3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d10a571-b51b-47a0-99a7-7279b31ff6bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_3f3a694a-7374-41e4-940c-7deb1f013e65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d10a571-b51b-47a0-99a7-7279b31ff6bb" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_3f3a694a-7374-41e4-940c-7deb1f013e65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_bd6b4961-42c4-4c72-bfb8-27289b6c3e9a" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d10a571-b51b-47a0-99a7-7279b31ff6bb" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_bd6b4961-42c4-4c72-bfb8-27289b6c3e9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_0b7a437c-270f-43a0-b9b8-fc81402a4cb6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d10a571-b51b-47a0-99a7-7279b31ff6bb" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_0b7a437c-270f-43a0-b9b8-fc81402a4cb6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d566f61e-d082-42b4-a879-017efe538805" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_8bc2f133-0ae2-4c60-adbe-a630f2b3f39a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d566f61e-d082-42b4-a879-017efe538805" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_d566f61e-d082-42b4-a879-017efe538805_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d566f61e-d082-42b4-a879-017efe538805" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_d566f61e-d082-42b4-a879-017efe538805_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d566f61e-d082-42b4-a879-017efe538805" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_3fe61875-e566-4f34-bf2f-5f4e6b2e0d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_us-gaap_CreditCardReceivablesMember_3fe61875-e566-4f34-bf2f-5f4e6b2e0d7b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherConsumerLoansMember_4c21864b-02d0-4e28-b019-dcb81b31afdb" xlink:href="sfnc-20210930.xsd#sfnc_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_sfnc_OtherConsumerLoansMember_4c21864b-02d0-4e28-b019-dcb81b31afdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_1137a5f8-40bd-40e0-96d5-a12b1a535cd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_us-gaap_ConstructionLoansMember_1137a5f8-40bd-40e0-96d5-a12b1a535cd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_0d473b3e-c9ca-4230-82dd-2fd62985e611" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_srt_SingleFamilyMember_0d473b3e-c9ca-4230-82dd-2fd62985e611" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_446df0ae-a367-4b22-ae58-65787587c63b" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_sfnc_OtherCommercialLoansMember_446df0ae-a367-4b22-ae58-65787587c63b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_af35067c-c93c-4451-b148-fef2fb6359e4" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_sfnc_CommercialLoansMember_af35067c-c93c-4451-b148-fef2fb6359e4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_AgriculturalLoansMember_ce0d7bd2-649e-4012-a56c-b730e630b53f" xlink:href="sfnc-20210930.xsd#sfnc_AgriculturalLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_1a627608-9291-4399-96b8-d2ddd7f0c9f8" xlink:to="loc_sfnc_AgriculturalLoansMember_ce0d7bd2-649e-4012-a56c-b730e630b53f" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesAgeAnalysisofPastDueLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesAgeAnalysisofPastDueLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesAgeAnalysisofPastDueLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="extended" id="icc458cfe9b934c17a62276d9eac70cc9_LoansandAllowanceforCreditLossesAgeAnalysisofPastDueLoansExcludingLoansAcquiredSegregatedbyClassofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f21c489-e0fc-4aad-9af7-9a0309bef15b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_3301750e-1770-4f4e-9106-b617e9f6da99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f21c489-e0fc-4aad-9af7-9a0309bef15b" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_3301750e-1770-4f4e-9106-b617e9f6da99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_d5d3db9b-3929-49e5-b1d1-554a01ba3cb6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f21c489-e0fc-4aad-9af7-9a0309bef15b" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_d5d3db9b-3929-49e5-b1d1-554a01ba3cb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_381ea3a4-198d-49d1-a303-e5450fa97306" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f21c489-e0fc-4aad-9af7-9a0309bef15b" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_381ea3a4-198d-49d1-a303-e5450fa97306" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04080819-8014-4153-9865-8afbf4d83d94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_381ea3a4-198d-49d1-a303-e5450fa97306" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04080819-8014-4153-9865-8afbf4d83d94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04080819-8014-4153-9865-8afbf4d83d94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04080819-8014-4153-9865-8afbf4d83d94" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04080819-8014-4153-9865-8afbf4d83d94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04080819-8014-4153-9865-8afbf4d83d94" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_949e9523-bb5c-4f5a-bb36-c19b2d5755db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_949e9523-bb5c-4f5a-bb36-c19b2d5755db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_5ab1691b-e994-4306-beae-d60acf7d9ecd" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_5ab1691b-e994-4306-beae-d60acf7d9ecd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_ec8b42f0-8d06-4c07-b3e9-252fd73cd8b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_ec8b42f0-8d06-4c07-b3e9-252fd73cd8b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnallocatedFinancingReceivablesMember_37dd424e-d406-4f2b-b639-0eff4a07ba10" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnallocatedFinancingReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f21cd65-d78f-4709-be38-2c66011ba8ee" xlink:to="loc_us-gaap_UnallocatedFinancingReceivablesMember_37dd424e-d406-4f2b-b639-0eff4a07ba10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_c9ace89c-627f-421b-b123-68027772a3ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_381ea3a4-198d-49d1-a303-e5450fa97306" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_c9ace89c-627f-421b-b123-68027772a3ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_c9ace89c-627f-421b-b123-68027772a3ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_c9ace89c-627f-421b-b123-68027772a3ab" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_c9ace89c-627f-421b-b123-68027772a3ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_c9ace89c-627f-421b-b123-68027772a3ab" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_47b5f577-1af6-4d71-a777-5eebbef272a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_us-gaap_CreditCardReceivablesMember_47b5f577-1af6-4d71-a777-5eebbef272a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherConsumerLoansMember_6e31cd63-cf7e-4f58-a3ae-d3df46a59e78" xlink:href="sfnc-20210930.xsd#sfnc_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_sfnc_OtherConsumerLoansMember_6e31cd63-cf7e-4f58-a3ae-d3df46a59e78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_d28a7edb-62fc-43d7-883e-dbd3a97c1e14" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_us-gaap_ConstructionLoansMember_d28a7edb-62fc-43d7-883e-dbd3a97c1e14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_8107d39a-2f09-4c3d-a61b-6f7d7e984a77" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_srt_SingleFamilyMember_8107d39a-2f09-4c3d-a61b-6f7d7e984a77" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_85d169bc-c000-40f9-9754-d76356d89f8e" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_sfnc_OtherCommercialLoansMember_85d169bc-c000-40f9-9754-d76356d89f8e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_6946521a-d28f-4d0b-ac08-b834bb49a571" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_sfnc_CommercialLoansMember_6946521a-d28f-4d0b-ac08-b834bb49a571" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_AgriculturalLoansMember_5e1df993-5dd9-48d2-81b5-45670386d8e5" xlink:href="sfnc-20210930.xsd#sfnc_AgriculturalLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8af37c8b-f736-4933-990c-90d29ca6a423" xlink:to="loc_sfnc_AgriculturalLoansMember_5e1df993-5dd9-48d2-81b5-45670386d8e5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_7dad2406-ef34-4f51-8d07-5e240db77453" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_381ea3a4-198d-49d1-a303-e5450fa97306" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_7dad2406-ef34-4f51-8d07-5e240db77453" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_7dad2406-ef34-4f51-8d07-5e240db77453_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_7dad2406-ef34-4f51-8d07-5e240db77453" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_7dad2406-ef34-4f51-8d07-5e240db77453_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_7dad2406-ef34-4f51-8d07-5e240db77453" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancingReceivables30To89DaysPastDueMember_3037fbe3-67b1-4746-a7a1-40370f54a41d" xlink:href="sfnc-20210930.xsd#sfnc_FinancingReceivables30To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:to="loc_sfnc_FinancingReceivables30To89DaysPastDueMember_3037fbe3-67b1-4746-a7a1-40370f54a41d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_b6978452-1814-42c5-89c0-703f6a3eff39" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_b6978452-1814-42c5-89c0-703f6a3eff39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_fe936f4d-ab54-43a6-af2b-2cfc6e937b78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_fe936f4d-ab54-43a6-af2b-2cfc6e937b78" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_ac8e882a-00c7-438b-a2e2-6e50c6e38256" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f360ddd3-0009-46cc-b1d5-72579fe1b948" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_ac8e882a-00c7-438b-a2e2-6e50c6e38256" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesTroubledDebtRestructuringsExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesTroubledDebtRestructuringsExcludingLoansAcquiredSegregatedbyClassofLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesTroubledDebtRestructuringsExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="extended" id="i6466f728618543c6b65d148c5a347840_LoansandAllowanceforCreditLossesTroubledDebtRestructuringsExcludingLoansAcquiredSegregatedbyClassofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_cf010ca9-a4b7-4e2e-8a0f-b55ded083a1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_28df27f4-16fd-44b8-9031-c749a63faea8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_cf010ca9-a4b7-4e2e-8a0f-b55ded083a1f" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_28df27f4-16fd-44b8-9031-c749a63faea8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_230d3409-50ee-431a-9dda-7728d943b61c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_cf010ca9-a4b7-4e2e-8a0f-b55ded083a1f" xlink:to="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_230d3409-50ee-431a-9dda-7728d943b61c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_cf010ca9-a4b7-4e2e-8a0f-b55ded083a1f" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5d8a7157-0981-4cdb-a417-1c9ded33398e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5d8a7157-0981-4cdb-a417-1c9ded33398e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d8a7157-0981-4cdb-a417-1c9ded33398e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5d8a7157-0981-4cdb-a417-1c9ded33398e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5d8a7157-0981-4cdb-a417-1c9ded33398e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_70c6592c-3fc4-4e3a-820a-8a379a43077e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5d8a7157-0981-4cdb-a417-1c9ded33398e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_70c6592c-3fc4-4e3a-820a-8a379a43077e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_43406393-63ab-485f-817e-35c129d9d9cb" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_70c6592c-3fc4-4e3a-820a-8a379a43077e" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_43406393-63ab-485f-817e-35c129d9d9cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_e49539cb-0ad0-4edc-b577-7f2c1bb82e57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_70c6592c-3fc4-4e3a-820a-8a379a43077e" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_e49539cb-0ad0-4edc-b577-7f2c1bb82e57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6eadd127-5286-4c81-b7fd-07962ebe4cf6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6eadd127-5286-4c81-b7fd-07962ebe4cf6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6eadd127-5286-4c81-b7fd-07962ebe4cf6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6eadd127-5286-4c81-b7fd-07962ebe4cf6" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6eadd127-5286-4c81-b7fd-07962ebe4cf6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9b410cbb-1756-4131-b03a-6e8e9abf226b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6eadd127-5286-4c81-b7fd-07962ebe4cf6" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9b410cbb-1756-4131-b03a-6e8e9abf226b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_386e5689-dd7e-40fa-9f9e-9248301c95ee" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9b410cbb-1756-4131-b03a-6e8e9abf226b" xlink:to="loc_srt_SingleFamilyMember_386e5689-dd7e-40fa-9f9e-9248301c95ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_484ed08b-6870-4919-a651-4179edec9ec8" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9b410cbb-1756-4131-b03a-6e8e9abf226b" xlink:to="loc_sfnc_OtherCommercialLoansMember_484ed08b-6870-4919-a651-4179edec9ec8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_e6db76dc-d1ee-45e0-9d58-16614775779d" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9b410cbb-1756-4131-b03a-6e8e9abf226b" xlink:to="loc_sfnc_CommercialLoansMember_e6db76dc-d1ee-45e0-9d58-16614775779d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_5c1b9835-fa66-419e-8680-bfe3811a6e98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_5c1b9835-fa66-419e-8680-bfe3811a6e98" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_5c1b9835-fa66-419e-8680-bfe3811a6e98_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_5c1b9835-fa66-419e-8680-bfe3811a6e98" xlink:to="loc_us-gaap_ReceivableTypeDomain_5c1b9835-fa66-419e-8680-bfe3811a6e98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_137d181d-a5ac-41e6-b5f8-7790f7ca55da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_5c1b9835-fa66-419e-8680-bfe3811a6e98" xlink:to="loc_us-gaap_ReceivableTypeDomain_137d181d-a5ac-41e6-b5f8-7790f7ca55da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_LoansExcludingAcquiredLoansMember_ba10422a-a099-46d0-bba6-4c1511dd48d2" xlink:href="sfnc-20210930.xsd#sfnc_LoansExcludingAcquiredLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_137d181d-a5ac-41e6-b5f8-7790f7ca55da" xlink:to="loc_sfnc_LoansExcludingAcquiredLoansMember_ba10422a-a099-46d0-bba6-4c1511dd48d2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_f9db4444-4596-4dc3-9d38-9a96a618f6f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_f9db4444-4596-4dc3-9d38-9a96a618f6f0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_f9db4444-4596-4dc3-9d38-9a96a618f6f0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_f9db4444-4596-4dc3-9d38-9a96a618f6f0" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_f9db4444-4596-4dc3-9d38-9a96a618f6f0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_7710cb49-b8b9-44ac-a4d3-97e211fbe75b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_f9db4444-4596-4dc3-9d38-9a96a618f6f0" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_7710cb49-b8b9-44ac-a4d3-97e211fbe75b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_6e03b2cc-d983-40f3-af7c-062f851d48ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PerformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_7710cb49-b8b9-44ac-a4d3-97e211fbe75b" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_6e03b2cc-d983-40f3-af7c-062f851d48ac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_e5f5b260-29eb-4440-a590-06a98a410eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonperformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_7710cb49-b8b9-44ac-a4d3-97e211fbe75b" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_e5f5b260-29eb-4440-a590-06a98a410eb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_649532a9-e152-4971-8374-a60ffa0953ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_649532a9-e152-4971-8374-a60ffa0953ac" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_649532a9-e152-4971-8374-a60ffa0953ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_649532a9-e152-4971-8374-a60ffa0953ac" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_649532a9-e152-4971-8374-a60ffa0953ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_62a92f93-d5f5-4f3b-8916-9445c3b0d596" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_649532a9-e152-4971-8374-a60ffa0953ac" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_62a92f93-d5f5-4f3b-8916-9445c3b0d596" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_ExtendedMaturityandPaymentDeferralMember_0a767241-d5f1-489c-acce-ea3f61633317" xlink:href="sfnc-20210930.xsd#sfnc_ExtendedMaturityandPaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_62a92f93-d5f5-4f3b-8916-9445c3b0d596" xlink:to="loc_sfnc_ExtendedMaturityandPaymentDeferralMember_0a767241-d5f1-489c-acce-ea3f61633317" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_92288931-d410-48bc-bf5d-e9d90d1a22d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_5e131820-97ce-434e-b3db-179dd0aa3bb9" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_92288931-d410-48bc-bf5d-e9d90d1a22d3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_92288931-d410-48bc-bf5d-e9d90d1a22d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_92288931-d410-48bc-bf5d-e9d90d1a22d3" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_92288931-d410-48bc-bf5d-e9d90d1a22d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_02d6d1db-e11a-4577-acd7-a001cc378bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_92288931-d410-48bc-bf5d-e9d90d1a22d3" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_02d6d1db-e11a-4577-acd7-a001cc378bd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_COVID19PandemicMember_e4238350-5f2f-46f3-9490-fcd0b5bc2779" xlink:href="sfnc-20210930.xsd#sfnc_COVID19PandemicMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_02d6d1db-e11a-4577-acd7-a001cc378bd4" xlink:to="loc_sfnc_COVID19PandemicMember_e4238350-5f2f-46f3-9490-fcd0b5bc2779" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoansRestructuredasTDRsExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesLoansRestructuredasTDRsExcludingLoansAcquiredSegregatedbyClassofLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoansRestructuredasTDRsExcludingLoansAcquiredSegregatedbyClassofLoansDetails" xlink:type="extended" id="i08f2e6cb35e5492f9b8955b78a255f1d_LoansandAllowanceforCreditLossesLoansRestructuredasTDRsExcludingLoansAcquiredSegregatedbyClassofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_4c5ba492-ab27-40d9-95bf-20c0477c5a93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_4c5ba492-ab27-40d9-95bf-20c0477c5a93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_17826b49-6dac-40fd-bc8c-a495fc3654d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:to="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_17826b49-6dac-40fd-bc8c-a495fc3654d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_df51a815-f3ce-49ff-b17a-f5876f4c440d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_df51a815-f3ce-49ff-b17a-f5876f4c440d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancialImpactOnDateOfRestructure_2c2dff2a-fccf-479c-b226-f5a19ab41c8a" xlink:href="sfnc-20210930.xsd#sfnc_FinancialImpactOnDateOfRestructure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:to="loc_sfnc_FinancialImpactOnDateOfRestructure_2c2dff2a-fccf-479c-b226-f5a19ab41c8a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_082433a9-cdc1-4453-9b15-590f5b430aca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_dfb79684-822d-4541-a3a9-5c0244cbbd78" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_082433a9-cdc1-4453-9b15-590f5b430aca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_d34aa10e-d452-4751-afca-2f51d6bb9088" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_082433a9-cdc1-4453-9b15-590f5b430aca" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_d34aa10e-d452-4751-afca-2f51d6bb9088" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_d34aa10e-d452-4751-afca-2f51d6bb9088_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_d34aa10e-d452-4751-afca-2f51d6bb9088" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_d34aa10e-d452-4751-afca-2f51d6bb9088_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_63097791-c5cf-450f-85e8-3ff06f1b2739" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_d34aa10e-d452-4751-afca-2f51d6bb9088" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_63097791-c5cf-450f-85e8-3ff06f1b2739" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_e19ed7d2-c088-45f5-b78f-d408452fbcb0" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_63097791-c5cf-450f-85e8-3ff06f1b2739" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_e19ed7d2-c088-45f5-b78f-d408452fbcb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_87012351-6b02-4dc7-bf75-f9114ed3b876" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_082433a9-cdc1-4453-9b15-590f5b430aca" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_87012351-6b02-4dc7-bf75-f9114ed3b876" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_87012351-6b02-4dc7-bf75-f9114ed3b876_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_87012351-6b02-4dc7-bf75-f9114ed3b876" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_87012351-6b02-4dc7-bf75-f9114ed3b876_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6689d036-7998-4e30-8f86-b31c39562a15" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_87012351-6b02-4dc7-bf75-f9114ed3b876" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6689d036-7998-4e30-8f86-b31c39562a15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_1e264d92-5af5-4e87-b5c2-d9e4c65b073c" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6689d036-7998-4e30-8f86-b31c39562a15" xlink:to="loc_sfnc_OtherCommercialLoansMember_1e264d92-5af5-4e87-b5c2-d9e4c65b073c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_275cd498-dd9b-4b95-b85c-884c5eb75f6f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6689d036-7998-4e30-8f86-b31c39562a15" xlink:to="loc_srt_SingleFamilyMember_275cd498-dd9b-4b95-b85c-884c5eb75f6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_b3ebfd89-97f1-4bf9-a94d-00983a183bff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_082433a9-cdc1-4453-9b15-590f5b430aca" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_b3ebfd89-97f1-4bf9-a94d-00983a183bff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_b3ebfd89-97f1-4bf9-a94d-00983a183bff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_b3ebfd89-97f1-4bf9-a94d-00983a183bff" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_b3ebfd89-97f1-4bf9-a94d-00983a183bff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_fafd7541-e74f-476a-8150-42d3bb29938a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_b3ebfd89-97f1-4bf9-a94d-00983a183bff" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_fafd7541-e74f-476a-8150-42d3bb29938a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_1df69cc6-c5a9-4153-b5ab-add184e76234" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_fafd7541-e74f-476a-8150-42d3bb29938a" xlink:to="loc_us-gaap_ExtendedMaturityMember_1df69cc6-c5a9-4153-b5ab-add184e76234" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualInterestRateReductionMember_adab53ae-15b5-4e7f-bd5c-fbb745e1b577" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_fafd7541-e74f-476a-8150-42d3bb29938a" xlink:to="loc_us-gaap_ContractualInterestRateReductionMember_adab53ae-15b5-4e7f-bd5c-fbb745e1b577" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoansbyCreditRiskRatingSegregatedbyClassofLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesLoansbyCreditRiskRatingSegregatedbyClassofLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesLoansbyCreditRiskRatingSegregatedbyClassofLoansDetails" xlink:type="extended" id="i905c20722b3743f393cef7efd00a724e_LoansandAllowanceforCreditLossesLoansbyCreditRiskRatingSegregatedbyClassofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_ee48971e-9a01-4d9c-855f-0724f91e7fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_ee48971e-9a01-4d9c-855f-0724f91e7fd0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_378a49ae-ec36-46bb-87b1-bb554f9c8d23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_378a49ae-ec36-46bb-87b1-bb554f9c8d23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_781691d7-fe04-4c88-909a-448cc8270a07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_781691d7-fe04-4c88-909a-448cc8270a07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_733dd70a-9a7c-4fe7-aa23-fd91c72cdc98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_733dd70a-9a7c-4fe7-aa23-fd91c72cdc98" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_6fac49d2-2f6a-4f9f-9a76-53edf21e8cc3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_6fac49d2-2f6a-4f9f-9a76-53edf21e8cc3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_2e1999e4-2600-494a-a783-0cdab56a3c29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_2e1999e4-2600-494a-a783-0cdab56a3c29" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_89bace1e-5faa-4cd9-9a80-f02e15e9eda4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolving"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_89bace1e-5faa-4cd9-9a80-f02e15e9eda4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_ae20ba1d-bf46-4d22-b774-aa98f9dbb719" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_ae20ba1d-bf46-4d22-b774-aa98f9dbb719" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_d2fca3da-9ec7-43f1-aedb-5b142a8c3098" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_d2fca3da-9ec7-43f1-aedb-5b142a8c3098" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_ea60ff2c-5317-45e6-a997-f32a913f1da3" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_3a0f3357-207f-4a1d-bcb1-dc9e6a54aa72" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_06206d67-795b-4602-9557-f61e8b0d3b15" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_06206d67-795b-4602-9557-f61e8b0d3b15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancialAsset30to89DaysPastDueMember_c983faaf-5e40-49e6-837b-c02dc99dcb9c" xlink:href="sfnc-20210930.xsd#sfnc_FinancialAsset30to89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:to="loc_sfnc_FinancialAsset30to89DaysPastDueMember_c983faaf-5e40-49e6-837b-c02dc99dcb9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_8ce1ea12-79d1-45cb-859e-5d31b7e5fb54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_8ce1ea12-79d1-45cb-859e-5d31b7e5fb54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancingReceivablesEqualToGreaterThan30DaysPastDueMember_db78a179-e6d8-4cad-a1f1-0f0c8e7ea9e1" xlink:href="sfnc-20210930.xsd#sfnc_FinancingReceivablesEqualToGreaterThan30DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_eda28d1b-18ae-4ffe-9b0b-c38012d3dbef" xlink:to="loc_sfnc_FinancingReceivablesEqualToGreaterThan30DaysPastDueMember_db78a179-e6d8-4cad-a1f1-0f0c8e7ea9e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_88468305-604c-4bf8-a98d-6d6335321931" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_88468305-604c-4bf8-a98d-6d6335321931" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_88468305-604c-4bf8-a98d-6d6335321931_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_88468305-604c-4bf8-a98d-6d6335321931" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_88468305-604c-4bf8-a98d-6d6335321931_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_88468305-604c-4bf8-a98d-6d6335321931" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_8db0f86b-d88e-42d7-a79b-a5b2c2869be2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_8db0f86b-d88e-42d7-a79b-a5b2c2869be2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_66c44c3c-0240-4a2c-8ca0-68a189ff14bf" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_66c44c3c-0240-4a2c-8ca0-68a189ff14bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_a492919b-56a7-4b1b-ba2f-0c9a65edb24f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_a492919b-56a7-4b1b-ba2f-0c9a65edb24f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnallocatedFinancingReceivablesMember_1c566437-1249-40bd-971f-a8b2906a99d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnallocatedFinancingReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c8e5e7c6-e441-454d-b5cb-53a41c3dfac3" xlink:to="loc_us-gaap_UnallocatedFinancingReceivablesMember_1c566437-1249-40bd-971f-a8b2906a99d0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d2ca8671-2fbe-4546-a3a6-4125b397581c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d2ca8671-2fbe-4546-a3a6-4125b397581c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_d2ca8671-2fbe-4546-a3a6-4125b397581c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d2ca8671-2fbe-4546-a3a6-4125b397581c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_d2ca8671-2fbe-4546-a3a6-4125b397581c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_d2ca8671-2fbe-4546-a3a6-4125b397581c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_cd2d5d1a-dc73-4fc2-b009-c6a76c542ca5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_us-gaap_CreditCardReceivablesMember_cd2d5d1a-dc73-4fc2-b009-c6a76c542ca5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherConsumerLoansMember_739499c2-2a18-481f-b8e7-f474f9e89cde" xlink:href="sfnc-20210930.xsd#sfnc_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_sfnc_OtherConsumerLoansMember_739499c2-2a18-481f-b8e7-f474f9e89cde" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_b76383da-bb4d-496e-8cb9-91724336daa2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_us-gaap_ConstructionLoansMember_b76383da-bb4d-496e-8cb9-91724336daa2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_5d29f8fe-709b-453c-9ff3-830da4af8bdc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_srt_SingleFamilyMember_5d29f8fe-709b-453c-9ff3-830da4af8bdc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_b55edd04-b4b4-43ca-9d80-cd4ee89d94c7" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_sfnc_OtherCommercialLoansMember_b55edd04-b4b4-43ca-9d80-cd4ee89d94c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_d5b37e3f-cd49-4a6d-8382-6691632e88d6" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_sfnc_CommercialLoansMember_d5b37e3f-cd49-4a6d-8382-6691632e88d6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_AgriculturalLoansMember_9ca41e0e-534b-4c32-82ff-0fa74f45b257" xlink:href="sfnc-20210930.xsd#sfnc_AgriculturalLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4018ddac-2242-460e-8158-60ca5a2f481e" xlink:to="loc_sfnc_AgriculturalLoansMember_9ca41e0e-534b-4c32-82ff-0fa74f45b257" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_d8530cce-5c02-4336-a37b-8e28fbba31ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_c6a15e9e-09c8-4bcc-9048-9d01fa80d8be" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_d8530cce-5c02-4336-a37b-8e28fbba31ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_d8530cce-5c02-4336-a37b-8e28fbba31ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d8530cce-5c02-4336-a37b-8e28fbba31ab" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_d8530cce-5c02-4336-a37b-8e28fbba31ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d8530cce-5c02-4336-a37b-8e28fbba31ab" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_75a50c48-0eaf-43f9-adff-3afa2faf16f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_us-gaap_PassMember_75a50c48-0eaf-43f9-adff-3afa2faf16f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_de90fde1-ea60-46b7-84b5-d54baf0e892d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_us-gaap_SpecialMentionMember_de90fde1-ea60-46b7-84b5-d54baf0e892d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_dbb8604f-67b7-46ec-9312-639edbabf282" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_us-gaap_SubstandardMember_dbb8604f-67b7-46ec-9312-639edbabf282" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_8ccbd9eb-7ef5-4dad-a597-6cc4bf622b57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_us-gaap_DoubtfulMember_8ccbd9eb-7ef5-4dad-a597-6cc4bf622b57" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CriticizedMember_f20d15f6-afd6-41f8-b7ec-5de6da49644f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CriticizedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_us-gaap_CriticizedMember_f20d15f6-afd6-41f8-b7ec-5de6da49644f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CriticizedAndPastDueMember_e25fbdd8-58b0-4992-bef2-ca0a790975d2" xlink:href="sfnc-20210930.xsd#sfnc_CriticizedAndPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_6e8d3105-1267-42b4-abd5-c55c7df191b9" xlink:to="loc_sfnc_CriticizedAndPastDueMember_e25fbdd8-58b0-4992-bef2-ca0a790975d2" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesCollateralDependentLoansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesCollateralDependentLoansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesCollateralDependentLoansDetails" xlink:type="extended" id="i7af8b1d023274de993e480fdfbef1ad3_LoansandAllowanceforCreditLossesCollateralDependentLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_fd4624d8-ab94-4383-b257-67843d703004" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinancingReceivableCollateralDependentAmount_734299b2-0e9c-4f9f-8d08-679d8b7033e0" xlink:href="sfnc-20210930.xsd#sfnc_FinancingReceivableCollateralDependentAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_fd4624d8-ab94-4383-b257-67843d703004" xlink:to="loc_sfnc_FinancingReceivableCollateralDependentAmount_734299b2-0e9c-4f9f-8d08-679d8b7033e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_c20c8dea-dd00-4a59-bf00-2f8e9599db29" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_fd4624d8-ab94-4383-b257-67843d703004" xlink:to="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_c20c8dea-dd00-4a59-bf00-2f8e9599db29" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_c20c8dea-dd00-4a59-bf00-2f8e9599db29" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ee1b7713-339f-4c6a-94d1-e7af8ce6dbe5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fdf90ff8-c9f6-4d05-b072-b97b8bc4ec7c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ee1b7713-339f-4c6a-94d1-e7af8ce6dbe5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_47404bf6-3800-4ab2-81f4-0c8dd7bec8c0" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ee1b7713-339f-4c6a-94d1-e7af8ce6dbe5" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_47404bf6-3800-4ab2-81f4-0c8dd7bec8c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_7f0d82d6-d10c-4bfe-b292-a113f0cfe308" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_ee1b7713-339f-4c6a-94d1-e7af8ce6dbe5" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_7f0d82d6-d10c-4bfe-b292-a113f0cfe308" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_77b8426e-8744-486b-bb3c-491c1be0f460" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_c20c8dea-dd00-4a59-bf00-2f8e9599db29" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_77b8426e-8744-486b-bb3c-491c1be0f460" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_77b8426e-8744-486b-bb3c-491c1be0f460_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_77b8426e-8744-486b-bb3c-491c1be0f460" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_77b8426e-8744-486b-bb3c-491c1be0f460_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_77b8426e-8744-486b-bb3c-491c1be0f460" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_4a91c59f-9b2a-4a9b-a7de-4567c28128b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:to="loc_us-gaap_ConstructionLoansMember_4a91c59f-9b2a-4a9b-a7de-4567c28128b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SingleFamilyMember_c2e82ee6-503f-4adb-a89f-938c3c79edf8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SingleFamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:to="loc_srt_SingleFamilyMember_c2e82ee6-503f-4adb-a89f-938c3c79edf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherCommercialLoansMember_77d70639-56ba-4a90-b03e-f1a78874debc" xlink:href="sfnc-20210930.xsd#sfnc_OtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:to="loc_sfnc_OtherCommercialLoansMember_77d70639-56ba-4a90-b03e-f1a78874debc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CommercialLoansMember_8565867c-cc02-4f57-a867-ead127033b8b" xlink:href="sfnc-20210930.xsd#sfnc_CommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_632393e7-2336-48fd-a1ae-1cf4b59216a2" xlink:to="loc_sfnc_CommercialLoansMember_8565867c-cc02-4f57-a867-ead127033b8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_65ad865b-410b-4dc7-bccd-099937e1ba41" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_c20c8dea-dd00-4a59-bf00-2f8e9599db29" xlink:to="loc_us-gaap_CollateralAxis_65ad865b-410b-4dc7-bccd-099937e1ba41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_65ad865b-410b-4dc7-bccd-099937e1ba41_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_65ad865b-410b-4dc7-bccd-099937e1ba41" xlink:to="loc_us-gaap_CollateralDomain_65ad865b-410b-4dc7-bccd-099937e1ba41_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_85df86b5-ac5c-438c-a69c-ed76f118a3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_65ad865b-410b-4dc7-bccd-099937e1ba41" xlink:to="loc_us-gaap_CollateralDomain_85df86b5-ac5c-438c-a69c-ed76f118a3c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateMember_3f489bfc-9897-4e3a-9e3a-431f72ed76e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_85df86b5-ac5c-438c-a69c-ed76f118a3c7" xlink:to="loc_us-gaap_RealEstateMember_3f489bfc-9897-4e3a-9e3a-431f72ed76e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SecuredEnergyProductionAssetsMember_6bf4c516-2a22-40b5-b8d2-b38dabc2fbf2" xlink:href="sfnc-20210930.xsd#sfnc_SecuredEnergyProductionAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_85df86b5-ac5c-438c-a69c-ed76f118a3c7" xlink:to="loc_sfnc_SecuredEnergyProductionAssetsMember_6bf4c516-2a22-40b5-b8d2-b38dabc2fbf2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherBusinessAssetsMember_5402b340-9519-4d50-9561-f057f659d6e5" xlink:href="sfnc-20210930.xsd#sfnc_OtherBusinessAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_85df86b5-ac5c-438c-a69c-ed76f118a3c7" xlink:to="loc_sfnc_OtherBusinessAssetsMember_5402b340-9519-4d50-9561-f057f659d6e5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesActivityintheAllowanceforLoanLossesbyPortfolioSegmentfortheCurrentYearDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#LoansandAllowanceforCreditLossesActivityintheAllowanceforLoanLossesbyPortfolioSegmentfortheCurrentYearDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/LoansandAllowanceforCreditLossesActivityintheAllowanceforLoanLossesbyPortfolioSegmentfortheCurrentYearDetails" xlink:type="extended" id="icee3cc859b3c4083be19d39faf816db4_LoansandAllowanceforCreditLossesActivityintheAllowanceforLoanLossesbyPortfolioSegmentfortheCurrentYearDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_3ddebc25-2423-4a74-a92c-a70fe35d8c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_3ddebc25-2423-4a74-a92c-a70fe35d8c9c" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_02b3ab49-a89b-4069-bd65-308944333e07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_02b3ab49-a89b-4069-bd65-308944333e07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_bec0de47-f830-4d58-87d7-ad22fa99f592" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_bec0de47-f830-4d58-87d7-ad22fa99f592" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_52acf89c-3f5a-4cc1-adf4-1ac6116742cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_52acf89c-3f5a-4cc1-adf4-1ac6116742cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_7a828aee-6dc0-48a6-aa26-8f71b6ace651" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_7a828aee-6dc0-48a6-aa26-8f71b6ace651" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery_452fbb68-e951-4900-bf22-7581f1cb8722" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_437931e1-3d85-4154-aa23-c65150ca0845" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery_452fbb68-e951-4900-bf22-7581f1cb8722" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_185225fd-d087-485c-84de-e73a226d9f06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_3ddebc25-2423-4a74-a92c-a70fe35d8c9c" xlink:to="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d47b117f-45fd-4bb6-a57b-8c0576b17c3c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d47b117f-45fd-4bb6-a57b-8c0576b17c3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d47b117f-45fd-4bb6-a57b-8c0576b17c3c_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d47b117f-45fd-4bb6-a57b-8c0576b17c3c" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d47b117f-45fd-4bb6-a57b-8c0576b17c3c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_88f267a1-9a47-4d9b-a5be-a6affcc6464d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d47b117f-45fd-4bb6-a57b-8c0576b17c3c" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_88f267a1-9a47-4d9b-a5be-a6affcc6464d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_0dbe3771-e59f-412e-bc01-0a84037e95cb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_88f267a1-9a47-4d9b-a5be-a6affcc6464d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_0dbe3771-e59f-412e-bc01-0a84037e95cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_4f45016e-0144-4fe8-a5c2-bccc1b731e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_4f45016e-0144-4fe8-a5c2-bccc1b731e2e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_4f45016e-0144-4fe8-a5c2-bccc1b731e2e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_4f45016e-0144-4fe8-a5c2-bccc1b731e2e" xlink:to="loc_us-gaap_ReceivableTypeDomain_4f45016e-0144-4fe8-a5c2-bccc1b731e2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_3945b758-7f31-461a-b1f7-480764b112c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_4f45016e-0144-4fe8-a5c2-bccc1b731e2e" xlink:to="loc_us-gaap_ReceivableTypeDomain_3945b758-7f31-461a-b1f7-480764b112c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_LoansExcludingAcquiredLoansMember_372c9c9e-90ab-4469-ba22-b3adb9e8daaa" xlink:href="sfnc-20210930.xsd#sfnc_LoansExcludingAcquiredLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_3945b758-7f31-461a-b1f7-480764b112c5" xlink:to="loc_sfnc_LoansExcludingAcquiredLoansMember_372c9c9e-90ab-4469-ba22-b3adb9e8daaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6d844f26-8f92-45b1-bc8e-b0f79dc016c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6d844f26-8f92-45b1-bc8e-b0f79dc016c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6d844f26-8f92-45b1-bc8e-b0f79dc016c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6d844f26-8f92-45b1-bc8e-b0f79dc016c1" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6d844f26-8f92-45b1-bc8e-b0f79dc016c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_87cc35ca-07d5-4582-9602-493b4f008e85" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6d844f26-8f92-45b1-bc8e-b0f79dc016c1" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_87cc35ca-07d5-4582-9602-493b4f008e85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_748a7dda-3f83-4660-91ee-723160312c6b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_87cc35ca-07d5-4582-9602-493b4f008e85" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_748a7dda-3f83-4660-91ee-723160312c6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RealEstatePortfolioSegmentMember_58dcb34a-9623-4651-97cf-dc110ce61acb" xlink:href="sfnc-20210930.xsd#sfnc_RealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_87cc35ca-07d5-4582-9602-493b4f008e85" xlink:to="loc_sfnc_RealEstatePortfolioSegmentMember_58dcb34a-9623-4651-97cf-dc110ce61acb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_2344e51e-f139-4d59-96fc-89b535c5f83f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_87cc35ca-07d5-4582-9602-493b4f008e85" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_2344e51e-f139-4d59-96fc-89b535c5f83f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_3c622a86-24c4-466f-a44c-368b36dbe322" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_06564098-d171-450c-bcbe-14ad58723384" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_3c622a86-24c4-466f-a44c-368b36dbe322" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_3c622a86-24c4-466f-a44c-368b36dbe322_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_3c622a86-24c4-466f-a44c-368b36dbe322" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_3c622a86-24c4-466f-a44c-368b36dbe322_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f496e26f-bb97-4f0c-b652-c793772703af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_3c622a86-24c4-466f-a44c-368b36dbe322" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f496e26f-bb97-4f0c-b652-c793772703af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_cb189174-b358-4b4d-b5c8-8caa4c7437fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f496e26f-bb97-4f0c-b652-c793772703af" xlink:to="loc_us-gaap_CreditCardReceivablesMember_cb189174-b358-4b4d-b5c8-8caa4c7437fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherLoansMember_92a3baab-fbde-4b1c-9ff6-e7767f53cf06" xlink:href="sfnc-20210930.xsd#sfnc_OtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f496e26f-bb97-4f0c-b652-c793772703af" xlink:to="loc_sfnc_OtherLoansMember_92a3baab-fbde-4b1c-9ff6-e7767f53cf06" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/PremisesandEquipmentDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#PremisesandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/PremisesandEquipmentDetails" xlink:type="extended" id="i4c31e09e42614b82adc2a6e01fc3abd5_PremisesandEquipmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_025c4236-3390-4daf-83cb-c60865e08d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_025c4236-3390-4daf-83cb-c60865e08d5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_c990b507-9cf6-4dcd-8724-4a33d31d737a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_c990b507-9cf6-4dcd-8724-4a33d31d737a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_bebec84b-3d06-46b4-a135-bd528e9c0c7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_bebec84b-3d06-46b4-a135-bd528e9c0c7e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_PropertyPlantandEquipmentandRightofUseAssetAccumulatedDepreciationandAmortization_25cbacdc-e78e-4c76-9111-4e20d6776fba" xlink:href="sfnc-20210930.xsd#sfnc_PropertyPlantandEquipmentandRightofUseAssetAccumulatedDepreciationandAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_sfnc_PropertyPlantandEquipmentandRightofUseAssetAccumulatedDepreciationandAmortization_25cbacdc-e78e-4c76-9111-4e20d6776fba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_PropertyPlantandEquipmentandRightofUseAssetafterAccumulatedDepreciationandAmortization_acbf3d70-68e9-4540-942b-3ecd71a8ff64" xlink:href="sfnc-20210930.xsd#sfnc_PropertyPlantandEquipmentandRightofUseAssetafterAccumulatedDepreciationandAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_sfnc_PropertyPlantandEquipmentandRightofUseAssetafterAccumulatedDepreciationandAmortization_acbf3d70-68e9-4540-942b-3ecd71a8ff64" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_451b47e8-2ee5-47c5-90b6-b5b094dba789" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3b0ad9ef-312f-440f-bd72-098f634a75e4" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_451b47e8-2ee5-47c5-90b6-b5b094dba789" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9d1df749-7ff5-4bdd-8043-7293da2ff37f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_451b47e8-2ee5-47c5-90b6-b5b094dba789" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9d1df749-7ff5-4bdd-8043-7293da2ff37f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9d1df749-7ff5-4bdd-8043-7293da2ff37f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9d1df749-7ff5-4bdd-8043-7293da2ff37f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9d1df749-7ff5-4bdd-8043-7293da2ff37f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9d1df749-7ff5-4bdd-8043-7293da2ff37f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_58882095-1982-40cc-b0db-dc0e78c6252c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:to="loc_us-gaap_LandMember_58882095-1982-40cc-b0db-dc0e78c6252c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_73de3b8b-3470-413f-99cd-25283282bd45" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_73de3b8b-3470-413f-99cd-25283282bd45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_83cb79e4-058b-4bb2-9320-d6e39c861593" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_83cb79e4-058b-4bb2-9320-d6e39c861593" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SoftwareMember_52303082-a9b4-4787-97f5-3c5194a6947d" xlink:href="sfnc-20210930.xsd#sfnc_SoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:to="loc_sfnc_SoftwareMember_52303082-a9b4-4787-97f5-3c5194a6947d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_c2d3179e-dfc5-4247-94ec-9051feb5fe84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7cd58334-653c-4dae-952a-27cb6b1cf3da" xlink:to="loc_us-gaap_ConstructionInProgressMember_c2d3179e-dfc5-4247-94ec-9051feb5fe84" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#GoodwillandOtherIntangibleAssetsTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsTextualDetails" xlink:type="extended" id="ia0a682f472b54f8e8cf3ae9103defcda_GoodwillandOtherIntangibleAssetsTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d9e6c78b-4ce6-40a1-83d8-90df3908ce91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_029fab45-30ed-43a1-8b66-6c6e006a44a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d9e6c78b-4ce6-40a1-83d8-90df3908ce91" xlink:to="loc_us-gaap_Goodwill_029fab45-30ed-43a1-8b66-6c6e006a44a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_50a2137a-6d6f-407d-84e1-6a48ccab1d6f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d9e6c78b-4ce6-40a1-83d8-90df3908ce91" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_50a2137a-6d6f-407d-84e1-6a48ccab1d6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_bb98ffad-f196-4b8a-8df7-35980310d9e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d9e6c78b-4ce6-40a1-83d8-90df3908ce91" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_bb98ffad-f196-4b8a-8df7-35980310d9e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_ecd660ad-bf3f-436f-ac6e-67ec8dcd326e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d9e6c78b-4ce6-40a1-83d8-90df3908ce91" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_ecd660ad-bf3f-436f-ac6e-67ec8dcd326e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a14d717f-9bb3-46c1-99be-d904399d4c04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_ecd660ad-bf3f-436f-ac6e-67ec8dcd326e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a14d717f-9bb3-46c1-99be-d904399d4c04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a14d717f-9bb3-46c1-99be-d904399d4c04_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a14d717f-9bb3-46c1-99be-d904399d4c04" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a14d717f-9bb3-46c1-99be-d904399d4c04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e6859201-c170-4a33-a14a-8da4c94e89aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a14d717f-9bb3-46c1-99be-d904399d4c04" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e6859201-c170-4a33-a14a-8da4c94e89aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CoreDepositPremiumMember_7cdc314c-6667-416f-8414-a8a4c011b841" xlink:href="sfnc-20210930.xsd#sfnc_CoreDepositPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e6859201-c170-4a33-a14a-8da4c94e89aa" xlink:to="loc_sfnc_CoreDepositPremiumMember_7cdc314c-6667-416f-8414-a8a4c011b841" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_692ca147-f6a7-48fd-9e4d-0199bd6f2087" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_ecd660ad-bf3f-436f-ac6e-67ec8dcd326e" xlink:to="loc_srt_RangeAxis_692ca147-f6a7-48fd-9e4d-0199bd6f2087" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_692ca147-f6a7-48fd-9e4d-0199bd6f2087_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_692ca147-f6a7-48fd-9e4d-0199bd6f2087" xlink:to="loc_srt_RangeMember_692ca147-f6a7-48fd-9e4d-0199bd6f2087_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bcf58c15-a83a-42f5-8db8-80a20e7d1d80" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_692ca147-f6a7-48fd-9e4d-0199bd6f2087" xlink:to="loc_srt_RangeMember_bcf58c15-a83a-42f5-8db8-80a20e7d1d80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_ecee99ab-6ff4-45ee-be4c-f0da1c194370" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_bcf58c15-a83a-42f5-8db8-80a20e7d1d80" xlink:to="loc_srt_MinimumMember_ecee99ab-6ff4-45ee-be4c-f0da1c194370" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_c9fa301b-d434-4220-88be-a2adb7b2e133" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_bcf58c15-a83a-42f5-8db8-80a20e7d1d80" xlink:to="loc_srt_MaximumMember_c9fa301b-d434-4220-88be-a2adb7b2e133" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsChangesinGoodwillandOtherIntangiblesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#GoodwillandOtherIntangibleAssetsChangesinGoodwillandOtherIntangiblesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsChangesinGoodwillandOtherIntangiblesDetails" xlink:type="extended" id="ibed1d44728d242b0a873e883f8b45a4d_GoodwillandOtherIntangibleAssetsChangesinGoodwillandOtherIntangiblesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_da239cac-3d9e-4132-ac67-d5d3b18a895a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_2d5e532d-974d-4ada-941c-14d597213611" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_da239cac-3d9e-4132-ac67-d5d3b18a895a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_2d5e532d-974d-4ada-941c-14d597213611" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_bda8393e-5cc6-4635-a89a-d274910c190b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_2d5e532d-974d-4ada-941c-14d597213611" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_bda8393e-5cc6-4635-a89a-d274910c190b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FinitelivedIntangibleAssetsDisposition_67e33088-86fc-414f-a5fe-18d77a40f23a" xlink:href="sfnc-20210930.xsd#sfnc_FinitelivedIntangibleAssetsDisposition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_2d5e532d-974d-4ada-941c-14d597213611" xlink:to="loc_sfnc_FinitelivedIntangibleAssetsDisposition_67e33088-86fc-414f-a5fe-18d77a40f23a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_aded7dae-8c26-4529-9073-2583d4355623" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_2d5e532d-974d-4ada-941c-14d597213611" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_aded7dae-8c26-4529-9073-2583d4355623" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_ee58f51f-2c5d-4a53-92e4-cc5d0d9c29d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e548e633-fe10-4798-b4f8-2da7cb2c7893" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_44551db5-bb58-469b-903a-005c8dafbc83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_da239cac-3d9e-4132-ac67-d5d3b18a895a" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_44551db5-bb58-469b-903a-005c8dafbc83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c15bc2-ea97-49b3-8d67-39ac27459562" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_44551db5-bb58-469b-903a-005c8dafbc83" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c15bc2-ea97-49b3-8d67-39ac27459562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_17c15bc2-ea97-49b3-8d67-39ac27459562_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c15bc2-ea97-49b3-8d67-39ac27459562" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_17c15bc2-ea97-49b3-8d67-39ac27459562_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45c41582-859a-46b8-a08a-80e37b209f8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c15bc2-ea97-49b3-8d67-39ac27459562" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45c41582-859a-46b8-a08a-80e37b209f8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CoreDepositPremiumMember_82fbda29-a27e-4340-af02-d90d6fd864ae" xlink:href="sfnc-20210930.xsd#sfnc_CoreDepositPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45c41582-859a-46b8-a08a-80e37b209f8b" xlink:to="loc_sfnc_CoreDepositPremiumMember_82fbda29-a27e-4340-af02-d90d6fd864ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BooksOfBusinessIntangibleMember_b4756353-79c1-4db8-b93a-7ba39be71cd3" xlink:href="sfnc-20210930.xsd#sfnc_BooksOfBusinessIntangibleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_45c41582-859a-46b8-a08a-80e37b209f8b" xlink:to="loc_sfnc_BooksOfBusinessIntangibleMember_b4756353-79c1-4db8-b93a-7ba39be71cd3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsGoodwillandOtherIntangiblesDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#GoodwillandOtherIntangibleAssetsGoodwillandOtherIntangiblesDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/GoodwillandOtherIntangibleAssetsGoodwillandOtherIntangiblesDetails" xlink:type="extended" id="if2910cf96eca4a6d81b2a102e38abfc3_GoodwillandOtherIntangibleAssetsGoodwillandOtherIntangiblesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_59744c52-e01c-4ce9-bbaa-71fff39cc943" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_652e6635-8649-4977-a22d-aa5b175452ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_59744c52-e01c-4ce9-bbaa-71fff39cc943" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_652e6635-8649-4977-a22d-aa5b175452ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_13ac0199-9550-44e8-bd89-17ef3a5a9ac4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_59744c52-e01c-4ce9-bbaa-71fff39cc943" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_13ac0199-9550-44e8-bd89-17ef3a5a9ac4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_fc719189-3a24-42c7-8fb3-1dd6d444e62c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_59744c52-e01c-4ce9-bbaa-71fff39cc943" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_fc719189-3a24-42c7-8fb3-1dd6d444e62c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8484f2ad-1874-4f7e-b8dc-ffa653aea10a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_59744c52-e01c-4ce9-bbaa-71fff39cc943" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8484f2ad-1874-4f7e-b8dc-ffa653aea10a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_accf21bb-4e7e-444b-bd58-f078f7c2ac6b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8484f2ad-1874-4f7e-b8dc-ffa653aea10a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_accf21bb-4e7e-444b-bd58-f078f7c2ac6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_accf21bb-4e7e-444b-bd58-f078f7c2ac6b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_accf21bb-4e7e-444b-bd58-f078f7c2ac6b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_accf21bb-4e7e-444b-bd58-f078f7c2ac6b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f4df01ab-ea20-48a0-b286-59f3d6354b91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_accf21bb-4e7e-444b-bd58-f078f7c2ac6b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f4df01ab-ea20-48a0-b286-59f3d6354b91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CoreDepositPremiumMember_6a98fc6f-eca4-4c07-88f3-44803157bc55" xlink:href="sfnc-20210930.xsd#sfnc_CoreDepositPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f4df01ab-ea20-48a0-b286-59f3d6354b91" xlink:to="loc_sfnc_CoreDepositPremiumMember_6a98fc6f-eca4-4c07-88f3-44803157bc55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_BooksOfBusinessIntangibleMember_1c3dd225-6c81-48ed-975d-a2ac97626490" xlink:href="sfnc-20210930.xsd#sfnc_BooksOfBusinessIntangibleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f4df01ab-ea20-48a0-b286-59f3d6354b91" xlink:to="loc_sfnc_BooksOfBusinessIntangibleMember_1c3dd225-6c81-48ed-975d-a2ac97626490" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/IncomeTaxesTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#IncomeTaxesTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/IncomeTaxesTextualDetails" xlink:type="extended" id="i44bf7dbd01804a49a676f5ce073a1b41_IncomeTaxesTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_87a10ffa-461e-4d43-b779-f92340450a76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_c0dc4655-a1a7-4d62-9902-8f66e2bd4409" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_87a10ffa-461e-4d43-b779-f92340450a76" xlink:to="loc_us-gaap_OperatingLossCarryforwards_c0dc4655-a1a7-4d62-9902-8f66e2bd4409" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OpenTaxYear_f40a2397-a82e-4791-94f2-ad43d800dab3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OpenTaxYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_87a10ffa-461e-4d43-b779-f92340450a76" xlink:to="loc_us-gaap_OpenTaxYear_f40a2397-a82e-4791-94f2-ad43d800dab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_8dc6d12d-ddf2-41e4-b19b-c3562422dfdb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_87a10ffa-461e-4d43-b779-f92340450a76" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_8dc6d12d-ddf2-41e4-b19b-c3562422dfdb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_8dc6d12d-ddf2-41e4-b19b-c3562422dfdb" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0af0a326-b20e-42df-961e-15ae534858ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e19cab1e-5588-456d-ae04-1e0cf6c6d6ed" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0af0a326-b20e-42df-961e-15ae534858ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_MetropolitanMember_233a47bc-bb7e-4ff6-9699-fbb483918678" xlink:href="sfnc-20210930.xsd#sfnc_MetropolitanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0af0a326-b20e-42df-961e-15ae534858ec" xlink:to="loc_sfnc_MetropolitanMember_233a47bc-bb7e-4ff6-9699-fbb483918678" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_b5817b60-6d61-4071-969e-c44447ff8ada" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_8dc6d12d-ddf2-41e4-b19b-c3562422dfdb" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_b5817b60-6d61-4071-969e-c44447ff8ada" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_b5817b60-6d61-4071-969e-c44447ff8ada_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_b5817b60-6d61-4071-969e-c44447ff8ada" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_b5817b60-6d61-4071-969e-c44447ff8ada_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_05f81df5-f6d0-4178-af38-697919125daf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_b5817b60-6d61-4071-969e-c44447ff8ada" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_05f81df5-f6d0-4178-af38-697919125daf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_35aaddce-b05f-49fb-a682-ad6b7513c613" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_05f81df5-f6d0-4178-af38-697919125daf" xlink:to="loc_us-gaap_DomesticCountryMember_35aaddce-b05f-49fb-a682-ad6b7513c613" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_bc6a8d46-c468-4c8f-a320-1c3be411ad1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_05f81df5-f6d0-4178-af38-697919125daf" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_bc6a8d46-c468-4c8f-a320-1c3be411ad1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodAxis_d8334cbc-4efd-4ba4-ad63-fec4b8bca469" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_8dc6d12d-ddf2-41e4-b19b-c3562422dfdb" xlink:to="loc_us-gaap_TaxPeriodAxis_d8334cbc-4efd-4ba4-ad63-fec4b8bca469" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_d8334cbc-4efd-4ba4-ad63-fec4b8bca469_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_d8334cbc-4efd-4ba4-ad63-fec4b8bca469" xlink:to="loc_us-gaap_TaxPeriodDomain_d8334cbc-4efd-4ba4-ad63-fec4b8bca469_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_53b1b1b5-f9fd-4dba-a5d8-8303d804ab5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_d8334cbc-4efd-4ba4-ad63-fec4b8bca469" xlink:to="loc_us-gaap_TaxPeriodDomain_53b1b1b5-f9fd-4dba-a5d8-8303d804ab5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarliestTaxYearMember_d8df4495-94d1-479f-beb3-27cb2a64a485" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarliestTaxYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_53b1b1b5-f9fd-4dba-a5d8-8303d804ab5c" xlink:to="loc_us-gaap_EarliestTaxYearMember_d8df4495-94d1-479f-beb3-27cb2a64a485" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/SecuritiesSoldUnderAgreementstoRepurchaseContractualMaturityoftheAgreementsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#SecuritiesSoldUnderAgreementstoRepurchaseContractualMaturityoftheAgreementsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/SecuritiesSoldUnderAgreementstoRepurchaseContractualMaturityoftheAgreementsDetails" xlink:type="extended" id="i613c41c480df4b9eb1bce4b201f142e3_SecuritiesSoldUnderAgreementstoRepurchaseContractualMaturityoftheAgreementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsLineItems_150eb0e9-76d9-4bfe-9c9a-ef7ba9442602" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement_3f3ec502-632d-4a10-9367-4461754295c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsLineItems_150eb0e9-76d9-4bfe-9c9a-ef7ba9442602" xlink:to="loc_us-gaap_FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement_3f3ec502-632d-4a10-9367-4461754295c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsTable_ec743817-97a3-4cce-9df3-7ac1b56a0d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsLineItems_150eb0e9-76d9-4bfe-9c9a-ef7ba9442602" xlink:to="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsTable_ec743817-97a3-4cce-9df3-7ac1b56a0d5e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_062530c4-eba9-466a-a406-d1add139d655" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsTable_ec743817-97a3-4cce-9df3-7ac1b56a0d5e" xlink:to="loc_us-gaap_FinancialInstrumentAxis_062530c4-eba9-466a-a406-d1add139d655" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_062530c4-eba9-466a-a406-d1add139d655_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_062530c4-eba9-466a-a406-d1add139d655" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_062530c4-eba9-466a-a406-d1add139d655_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b7dd2a33-6ced-4789-882c-ab00ad21b045" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_062530c4-eba9-466a-a406-d1add139d655" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b7dd2a33-6ced-4789-882c-ab00ad21b045" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_d440a74d-ce12-48f1-aac2-be9f3f4a5356" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b7dd2a33-6ced-4789-882c-ab00ad21b045" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_d440a74d-ce12-48f1-aac2-be9f3f4a5356" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_226ef892-c9f6-4c44-a110-1d961a1f1343" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TransferOfCertainFinancialAssetsAccountedForAsSecuredBorrowingsTable_ec743817-97a3-4cce-9df3-7ac1b56a0d5e" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_226ef892-c9f6-4c44-a110-1d961a1f1343" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_226ef892-c9f6-4c44-a110-1d961a1f1343_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_226ef892-c9f6-4c44-a110-1d961a1f1343" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_226ef892-c9f6-4c44-a110-1d961a1f1343_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_226ef892-c9f6-4c44-a110-1d961a1f1343" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityOvernightMember_04cfa4f8-f392-4632-badf-cff0636a6a22" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MaturityOvernightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:to="loc_us-gaap_MaturityOvernightMember_04cfa4f8-f392-4632-badf-cff0636a6a22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityUpTo30DaysMember_25e7a08c-5b7c-496a-883b-36bd778fec6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MaturityUpTo30DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:to="loc_us-gaap_MaturityUpTo30DaysMember_25e7a08c-5b7c-496a-883b-36bd778fec6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Maturity30To90DaysMember_c98cea1a-0182-4d4d-a3f5-7cecc4c2c779" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Maturity30To90DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:to="loc_us-gaap_Maturity30To90DaysMember_c98cea1a-0182-4d4d-a3f5-7cecc4c2c779" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityOver90DaysMember_00ceac9f-73e9-4767-bf0a-9a605a76918e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MaturityOver90DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_b0e29bba-5c87-484b-af68-b829e4113557" xlink:to="loc_us-gaap_MaturityOver90DaysMember_00ceac9f-73e9-4767-bf0a-9a605a76918e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/OtherBorrowingsandSubordinatedNotesandDebenturesDebtComponentsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#OtherBorrowingsandSubordinatedNotesandDebenturesDebtComponentsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/OtherBorrowingsandSubordinatedNotesandDebenturesDebtComponentsDetails" xlink:type="extended" id="i1adf05f0c56f40ebbd1cdea905c2c1aa_OtherBorrowingsandSubordinatedNotesandDebenturesDebtComponentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_b486fba3-954f-436f-bc94-8e79485b5270" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_LongTermDebt_b486fba3-954f-436f-bc94-8e79485b5270" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_292c3a0b-e080-4121-bf91-096eb027411c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_292c3a0b-e080-4121-bf91-096eb027411c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_ba028b38-c4de-4319-aa99-ac57238e086d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_ba028b38-c4de-4319-aa99-ac57238e086d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_421f6862-87c1-4355-bb18-e652d4ffeb35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_421f6862-87c1-4355-bb18-e652d4ffeb35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_25632732-c438-4501-be49-34c9064fe231" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_25632732-c438-4501-be49-34c9064fe231" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0fa53643-62d1-4621-804e-4455528bd7e0" xlink:to="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_605150d2-3119-4c2d-a49e-279f029dac94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_605150d2-3119-4c2d-a49e-279f029dac94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_605150d2-3119-4c2d-a49e-279f029dac94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_605150d2-3119-4c2d-a49e-279f029dac94" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_605150d2-3119-4c2d-a49e-279f029dac94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_605150d2-3119-4c2d-a49e-279f029dac94" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMember_7220930a-4e19-4813-aa05-120462fd955a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMember_7220930a-4e19-4813-aa05-120462fd955a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherLongTermDebtMember_6cc67d14-dfb6-4557-883b-e969c21b7395" xlink:href="sfnc-20210930.xsd#sfnc_OtherLongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:to="loc_sfnc_OtherLongTermDebtMember_6cc67d14-dfb6-4557-883b-e969c21b7395" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FederalHomeLoanBankAdvanceandOtherLongTermDebtMember_c567d400-4052-4302-9229-bc2e37ac8f04" xlink:href="sfnc-20210930.xsd#sfnc_FederalHomeLoanBankAdvanceandOtherLongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:to="loc_sfnc_FederalHomeLoanBankAdvanceandOtherLongTermDebtMember_c567d400-4052-4302-9229-bc2e37ac8f04" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_60f868f5-eab8-4760-b0d7-b54fe2f6c5be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:to="loc_us-gaap_SubordinatedDebtMember_60f868f5-eab8-4760-b0d7-b54fe2f6c5be" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SubordinatedDebtandUnsecuredDebtMember_4281d441-54ae-4808-9cdf-4f259afe55fe" xlink:href="sfnc-20210930.xsd#sfnc_SubordinatedDebtandUnsecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2f5b4251-80a9-451b-adeb-a0e7a0736769" xlink:to="loc_sfnc_SubordinatedDebtandUnsecuredDebtMember_4281d441-54ae-4808-9cdf-4f259afe55fe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_e28fc640-7a10-49c6-a1ed-07a2af8d43bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:to="loc_us-gaap_DebtInstrumentAxis_e28fc640-7a10-49c6-a1ed-07a2af8d43bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_e28fc640-7a10-49c6-a1ed-07a2af8d43bc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_e28fc640-7a10-49c6-a1ed-07a2af8d43bc" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_e28fc640-7a10-49c6-a1ed-07a2af8d43bc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_e28fc640-7a10-49c6-a1ed-07a2af8d43bc" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_SubordinatedNotesPayableDue04012028Member_8b9afed4-432a-41c5-b34e-40971ca35ac9" xlink:href="sfnc-20210930.xsd#sfnc_SubordinatedNotesPayableDue04012028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_SubordinatedNotesPayableDue04012028Member_8b9afed4-432a-41c5-b34e-40971ca35ac9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TrustPreferredSecuritiesDue9152037Member_2452ed8d-ac62-4b98-97c3-de4a5c5d6607" xlink:href="sfnc-20210930.xsd#sfnc_TrustPreferredSecuritiesDue9152037Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_TrustPreferredSecuritiesDue9152037Member_2452ed8d-ac62-4b98-97c3-de4a5c5d6607" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TrustPreferredSecuritiesDue662037Member_ee86ad56-6ee6-45a2-9280-9ba8f079bfa0" xlink:href="sfnc-20210930.xsd#sfnc_TrustPreferredSecuritiesDue662037Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_TrustPreferredSecuritiesDue662037Member_ee86ad56-6ee6-45a2-9280-9ba8f079bfa0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TrustPreferredSecuritiesDue12152035Member_44f1cf4e-7244-48ed-ac3f-be587a9ceea9" xlink:href="sfnc-20210930.xsd#sfnc_TrustPreferredSecuritiesDue12152035Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_TrustPreferredSecuritiesDue12152035Member_44f1cf4e-7244-48ed-ac3f-be587a9ceea9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TrustPreferredSecuritiesDue6152037Member_734ada18-96b7-4246-95eb-29c232a1532b" xlink:href="sfnc-20210930.xsd#sfnc_TrustPreferredSecuritiesDue6152037Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_TrustPreferredSecuritiesDue6152037Member_734ada18-96b7-4246-95eb-29c232a1532b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TrustPreferredSecuritiesDue12152036Member_98c4a75a-b3ab-47ee-8fb9-6ce81e6af790" xlink:href="sfnc-20210930.xsd#sfnc_TrustPreferredSecuritiesDue12152036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1beb72c8-82db-4e23-8d30-0e5c68950b9e" xlink:to="loc_sfnc_TrustPreferredSecuritiesDue12152036Member_98c4a75a-b3ab-47ee-8fb9-6ce81e6af790" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:to="loc_us-gaap_VariableRateAxis_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b" xlink:to="loc_us-gaap_VariableRateDomain_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_5d6df00b-45f5-46e0-b7f7-725c8bafdbd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_b9ae877f-6eb1-46d2-aaee-c370c95e4c2b" xlink:to="loc_us-gaap_VariableRateDomain_5d6df00b-45f5-46e0-b7f7-725c8bafdbd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_1fc6cf27-fc6f-439c-8dfb-deff7d45545b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_5d6df00b-45f5-46e0-b7f7-725c8bafdbd0" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_1fc6cf27-fc6f-439c-8dfb-deff7d45545b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_73608185-95f2-49af-baae-63840b12d37b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_48408dfa-8ad7-4ec2-aa89-8ff6c400e422" xlink:to="loc_srt_RangeAxis_73608185-95f2-49af-baae-63840b12d37b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_73608185-95f2-49af-baae-63840b12d37b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_73608185-95f2-49af-baae-63840b12d37b" xlink:to="loc_srt_RangeMember_73608185-95f2-49af-baae-63840b12d37b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5cb482f0-d813-4a24-a25b-dc389a773e07" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_73608185-95f2-49af-baae-63840b12d37b" xlink:to="loc_srt_RangeMember_5cb482f0-d813-4a24-a25b-dc389a773e07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_436a1b0d-496f-4e06-8110-e8ac1c629791" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5cb482f0-d813-4a24-a25b-dc389a773e07" xlink:to="loc_srt_MinimumMember_436a1b0d-496f-4e06-8110-e8ac1c629791" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a236a7d2-7c36-4ab0-8cf5-529827c909a5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5cb482f0-d813-4a24-a25b-dc389a773e07" xlink:to="loc_srt_MaximumMember_a236a7d2-7c36-4ab0-8cf5-529827c909a5" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/OtherBorrowingsandSubordinatedNotesandDebenturesTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#OtherBorrowingsandSubordinatedNotesandDebenturesTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/OtherBorrowingsandSubordinatedNotesandDebenturesTextualDetails" xlink:type="extended" id="i0fa8ed001a564483a87669a8bb1b297a_OtherBorrowingsandSubordinatedNotesandDebenturesTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_a02949e3-2d22-4673-b5ce-e501d444f588" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_a02949e3-2d22-4673-b5ce-e501d444f588" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_18639949-d0f2-4a61-9d4f-d52abb23b020" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_18639949-d0f2-4a61-9d4f-d52abb23b020" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_8e090622-d959-41e0-b268-164f36162e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_8e090622-d959-41e0-b268-164f36162e7d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_002fffbc-cd32-46aa-85b2-a08548d085c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_002fffbc-cd32-46aa-85b2-a08548d085c3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_a0182b0f-8cf8-4e3e-a292-9f3a418bbdf7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdvancesFromFederalHomeLoanBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_a0182b0f-8cf8-4e3e-a292-9f3a418bbdf7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_203a2939-0801-481a-b836-7c500862db4d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_203a2939-0801-481a-b836-7c500862db4d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_3a6f1504-21c4-4380-a8e7-6b2a3b96704c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DebtInstrumentTerm_3a6f1504-21c4-4380-a8e7-6b2a3b96704c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_91ce0b26-c756-4e0b-8775-f31930c7c523" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_91ce0b26-c756-4e0b-8775-f31930c7c523" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_AdvancesFromFederalHomeLoanBankAvailable_80f3ca57-f56c-4408-b73d-e6691fd5d47e" xlink:href="sfnc-20210930.xsd#sfnc_AdvancesFromFederalHomeLoanBankAvailable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_sfnc_AdvancesFromFederalHomeLoanBankAvailable_80f3ca57-f56c-4408-b73d-e6691fd5d47e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23176eb4-c4e4-415a-87dd-000356c04a9a" xlink:to="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_930fc9b1-d9e4-401c-9cab-ed05925df757" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_930fc9b1-d9e4-401c-9cab-ed05925df757" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_930fc9b1-d9e4-401c-9cab-ed05925df757_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_930fc9b1-d9e4-401c-9cab-ed05925df757" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_930fc9b1-d9e4-401c-9cab-ed05925df757_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d187f75b-f8ea-47ef-99a5-a907f64ef207" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_930fc9b1-d9e4-401c-9cab-ed05925df757" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d187f75b-f8ea-47ef-99a5-a907f64ef207" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_f4f6ca7a-3d6e-44c4-b79a-1b383af17896" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d187f75b-f8ea-47ef-99a5-a907f64ef207" xlink:to="loc_us-gaap_SubordinatedDebtMember_f4f6ca7a-3d6e-44c4-b79a-1b383af17896" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_e371f615-fe47-4078-a131-a75e00c29c2b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:to="loc_us-gaap_DebtInstrumentAxis_e371f615-fe47-4078-a131-a75e00c29c2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_e371f615-fe47-4078-a131-a75e00c29c2b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_e371f615-fe47-4078-a131-a75e00c29c2b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_e371f615-fe47-4078-a131-a75e00c29c2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01e43608-625b-4f53-b26b-c1545d3115e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_e371f615-fe47-4078-a131-a75e00c29c2b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01e43608-625b-4f53-b26b-c1545d3115e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FederalHomeLoanBankOwnstheOptionsFOTOAdvancesMember_0bca7e01-66da-498a-ad72-d3b252b0d432" xlink:href="sfnc-20210930.xsd#sfnc_FederalHomeLoanBankOwnstheOptionsFOTOAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01e43608-625b-4f53-b26b-c1545d3115e9" xlink:to="loc_sfnc_FederalHomeLoanBankOwnstheOptionsFOTOAdvancesMember_0bca7e01-66da-498a-ad72-d3b252b0d432" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:to="loc_srt_RangeAxis_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb" xlink:to="loc_srt_RangeMember_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_452fcdf5-f60b-45a0-86e4-ddb85a4e3a23" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b6c91af3-e1cb-4fa3-b862-8345dfa5bbdb" xlink:to="loc_srt_RangeMember_452fcdf5-f60b-45a0-86e4-ddb85a4e3a23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_7b83e77a-8b7e-4d12-80bf-b81aab021ad1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_452fcdf5-f60b-45a0-86e4-ddb85a4e3a23" xlink:to="loc_srt_MinimumMember_7b83e77a-8b7e-4d12-80bf-b81aab021ad1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_aa0524f6-b692-4b0e-a148-b87e36763541" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_452fcdf5-f60b-45a0-86e4-ddb85a4e3a23" xlink:to="loc_srt_MaximumMember_aa0524f6-b692-4b0e-a148-b87e36763541" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f6304532-d3da-4c1f-a368-d52ceee84a0a" xlink:to="loc_us-gaap_VariableRateAxis_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf" xlink:to="loc_us-gaap_VariableRateDomain_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_7d4ada76-9c2a-48cd-94e0-f54212f84c1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_829d75ac-7fb0-48e1-bbbe-eb4d01be47cf" xlink:to="loc_us-gaap_VariableRateDomain_7d4ada76-9c2a-48cd-94e0-f54212f84c1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_1ab0827e-a940-42ad-853f-522492019beb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_7d4ada76-9c2a-48cd-94e0-f54212f84c1f" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_1ab0827e-a940-42ad-853f-522492019beb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/CapitalStockTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#CapitalStockTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/CapitalStockTextualDetails" xlink:type="extended" id="ib58a3a8cacc945ed8002b7e6d2fb0a12_CapitalStockTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_f8e90a5c-f1c7-4e20-9198-9378b4dbd2fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_f8e90a5c-f1c7-4e20-9198-9378b4dbd2fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_bbc39c9e-91f0-4060-8ef1-3be370e97abe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_bbc39c9e-91f0-4060-8ef1-3be370e97abe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreferenceValue_03225964-a14d-467d-8b1c-eef7d27ff22c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockLiquidationPreferenceValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_PreferredStockLiquidationPreferenceValue_03225964-a14d-467d-8b1c-eef7d27ff22c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_cd6c0133-2fd0-4440-8d75-73ff37277b2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_cd6c0133-2fd0-4440-8d75-73ff37277b2e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_52d304e6-3154-403c-9e4c-2c4d16cdc153" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_52d304e6-3154-403c-9e4c-2c4d16cdc153" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_StockRepurchasedDuringPeriodValueAverage_a49cbae9-7b61-4aea-b875-46637a2e946c" xlink:href="sfnc-20210930.xsd#sfnc_StockRepurchasedDuringPeriodValueAverage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_sfnc_StockRepurchasedDuringPeriodValueAverage_a49cbae9-7b61-4aea-b875-46637a2e946c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_bccfc0ad-2138-4248-bdd0-d58412b80722" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_27a9d0f2-f854-452e-a7d7-b9da091a2f44" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_bccfc0ad-2138-4248-bdd0-d58412b80722" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_fd119479-22b0-4d09-bf2b-7563e6083210" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_bccfc0ad-2138-4248-bdd0-d58412b80722" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_fd119479-22b0-4d09-bf2b-7563e6083210" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fd119479-22b0-4d09-bf2b-7563e6083210_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fd119479-22b0-4d09-bf2b-7563e6083210" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fd119479-22b0-4d09-bf2b-7563e6083210_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21e9de4a-f2ea-4dc1-9e5c-ad3b3963c957" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fd119479-22b0-4d09-bf2b-7563e6083210" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21e9de4a-f2ea-4dc1-9e5c-ad3b3963c957" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RelianceBancsharesInc.Member_6cf29d17-e30e-435d-be9f-cc2eeaefb1e3" xlink:href="sfnc-20210930.xsd#sfnc_RelianceBancsharesInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21e9de4a-f2ea-4dc1-9e5c-ad3b3963c957" xlink:to="loc_sfnc_RelianceBancsharesInc.Member_6cf29d17-e30e-435d-be9f-cc2eeaefb1e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_07245944-8f46-4358-a0f4-c74c4b0c9450" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_bccfc0ad-2138-4248-bdd0-d58412b80722" xlink:to="loc_srt_RangeAxis_07245944-8f46-4358-a0f4-c74c4b0c9450" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_07245944-8f46-4358-a0f4-c74c4b0c9450_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_07245944-8f46-4358-a0f4-c74c4b0c9450" xlink:to="loc_srt_RangeMember_07245944-8f46-4358-a0f4-c74c4b0c9450_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_eda2f855-b6bd-46f6-8b84-5f78ee00b09d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_07245944-8f46-4358-a0f4-c74c4b0c9450" xlink:to="loc_srt_RangeMember_eda2f855-b6bd-46f6-8b84-5f78ee00b09d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_79c2b178-6c6f-4f8e-bde9-477eaee9aeab" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_eda2f855-b6bd-46f6-8b84-5f78ee00b09d" xlink:to="loc_srt_MaximumMember_79c2b178-6c6f-4f8e-bde9-477eaee9aeab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_bccfc0ad-2138-4248-bdd0-d58412b80722" xlink:to="loc_us-gaap_StatementClassOfStockAxis_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e" xlink:to="loc_us-gaap_ClassOfStockDomain_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_0b6e32b0-2b36-4129-918e-3adb13ffe9e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_eaca6884-f7c4-4002-937a-b6f5c5f3cb7e" xlink:to="loc_us-gaap_ClassOfStockDomain_0b6e32b0-2b36-4129-918e-3adb13ffe9e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesDPreferredStockMember_a0d6f7af-14a9-4d29-811d-2de5ce1477d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesDPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0b6e32b0-2b36-4129-918e-3adb13ffe9e1" xlink:to="loc_us-gaap_SeriesDPreferredStockMember_a0d6f7af-14a9-4d29-811d-2de5ce1477d3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/StockBasedCompensationStockCompensationPlansDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#StockBasedCompensationStockCompensationPlansDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/StockBasedCompensationStockCompensationPlansDetails" xlink:type="extended" id="ibc164c35df7d43d18fea93d41caed250_StockBasedCompensationStockCompensationPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_0fc89c46-8a8e-49fd-a75c-5e5bcca6c96d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_0fc89c46-8a8e-49fd-a75c-5e5bcca6c96d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_c7643554-7b8d-4cde-9efb-2a8cc7eacb27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_c7643554-7b8d-4cde-9efb-2a8cc7eacb27" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_d0087f6f-6912-4a34-b3ff-f326b366f069" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_d0087f6f-6912-4a34-b3ff-f326b366f069" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_22652a2b-17cf-4e22-ac4a-9f17bd3d02e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_fde52a98-9ebb-401e-96b7-c7203e57006a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_22652a2b-17cf-4e22-ac4a-9f17bd3d02e4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_443430b4-6c20-4fda-aa80-e261cd4a32ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_1f8c3de9-2417-4ad1-9301-03446d7f2767" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_1f8c3de9-2417-4ad1-9301-03446d7f2767" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_cf499456-33fc-4efe-9275-21271f700abb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_cf499456-33fc-4efe-9275-21271f700abb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_60ecfb9c-c3ac-4a6a-8052-690f9d2675e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_60ecfb9c-c3ac-4a6a-8052-690f9d2675e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_ea1c64f2-992c-4220-9e4a-12bb1e3a7ccf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_ea1c64f2-992c-4220-9e4a-12bb1e3a7ccf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_83c71dfe-72e3-4d86-b4c9-1ea78b9c4e71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_fd6cbee5-b7bf-4a9b-bdc2-f9c31fabc967" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_83c71dfe-72e3-4d86-b4c9-1ea78b9c4e71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_e45089c8-8821-4e0d-b11d-2b88bb32aaad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_5f48f3e3-e92b-4604-8d31-836d797d1465" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_5f48f3e3-e92b-4604-8d31-836d797d1465" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_97479b35-17ab-4eb0-a866-c241010c90ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_97479b35-17ab-4eb0-a866-c241010c90ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_01fc70de-5133-46f8-b2df-71fe4e66112d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_01fc70de-5133-46f8-b2df-71fe4e66112d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_e9403a85-2124-4020-a5c1-b370bc3d9876" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_e9403a85-2124-4020-a5c1-b370bc3d9876" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_96fd6fb2-c0a8-486b-8177-8919cd96b3d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_4e8bf1c8-b6f9-4bf5-b990-c9fb593fc7cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_96fd6fb2-c0a8-486b-8177-8919cd96b3d1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_72e920d7-ebd4-4f80-8907-27adc93bf5c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_38de76af-a467-499d-bf44-2f95ba12dd74" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_38de76af-a467-499d-bf44-2f95ba12dd74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_609e7a46-8640-43c2-a84f-048b3b23638f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_609e7a46-8640-43c2-a84f-048b3b23638f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_1aaad622-aa07-4772-a1cf-9e706d75a754" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_1aaad622-aa07-4772-a1cf-9e706d75a754" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8ce86a2e-8706-4935-9e25-f1df60283d09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8020f703-bbdb-4797-b195-f56e3598a7ca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8ce86a2e-8706-4935-9e25-f1df60283d09" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_81a5e5f9-4f70-4d1e-8429-cb2651aebd83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_42ad4104-cd88-414d-83a9-967d6265904c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f946dd9-0b35-48c2-90d0-c34f14a58b61" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_42ad4104-cd88-414d-83a9-967d6265904c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_1bcace1d-29c7-402d-b630-b95f55fc8188" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_42ad4104-cd88-414d-83a9-967d6265904c" xlink:to="loc_us-gaap_AwardTypeAxis_1bcace1d-29c7-402d-b630-b95f55fc8188" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1bcace1d-29c7-402d-b630-b95f55fc8188_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_1bcace1d-29c7-402d-b630-b95f55fc8188" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1bcace1d-29c7-402d-b630-b95f55fc8188_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_46a91d9c-ffa5-4308-b8d0-e6b383da1eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_1bcace1d-29c7-402d-b630-b95f55fc8188" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_46a91d9c-ffa5-4308-b8d0-e6b383da1eb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_398af832-1eaf-4836-986c-3fee05c99fed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_46a91d9c-ffa5-4308-b8d0-e6b383da1eb4" xlink:to="loc_us-gaap_RestrictedStockMember_398af832-1eaf-4836-986c-3fee05c99fed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_StockUnitsMember_9392714a-e2aa-48aa-aa83-c9e424e3f51f" xlink:href="sfnc-20210930.xsd#sfnc_StockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_46a91d9c-ffa5-4308-b8d0-e6b383da1eb4" xlink:to="loc_sfnc_StockUnitsMember_9392714a-e2aa-48aa-aa83-c9e424e3f51f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/StockBasedCompensationStockOptionsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#StockBasedCompensationStockOptionsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/StockBasedCompensationStockOptionsDetails" xlink:type="extended" id="i7405b684c1d347e3b1e697405343e72d_StockBasedCompensationStockOptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_3821232e-fa81-4552-8b0b-70632a06858d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_3821232e-fa81-4552-8b0b-70632a06858d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_fb74f665-cc51-4255-91dc-57acf9ec9257" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_fb74f665-cc51-4255-91dc-57acf9ec9257" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_a2c5c2e9-2721-47f2-8eeb-1ea2b97f9edf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_a2c5c2e9-2721-47f2-8eeb-1ea2b97f9edf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_237e1c81-5842-4542-aac4-47c94c5a6f88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_237e1c81-5842-4542-aac4-47c94c5a6f88" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_25ba999b-9ebf-498c-9dda-0e9239f26b37" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_25ba999b-9ebf-498c-9dda-0e9239f26b37" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_9a7b0cb5-e998-41bc-84ea-225d9e839e56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_9a7b0cb5-e998-41bc-84ea-225d9e839e56" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_ac1c7fea-c3a6-4d80-b846-6b5073c18ff1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_ac1c7fea-c3a6-4d80-b846-6b5073c18ff1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_33fdbcd0-5076-4b46-b49e-67935c60ddc0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_083d7060-bf5c-4aa8-92bb-bb9be341ec2d" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_33fdbcd0-5076-4b46-b49e-67935c60ddc0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_dd6bdad4-50e1-42d2-b449-3f704dddc348" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_33fdbcd0-5076-4b46-b49e-67935c60ddc0" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_dd6bdad4-50e1-42d2-b449-3f704dddc348" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_dd6bdad4-50e1-42d2-b449-3f704dddc348_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_dd6bdad4-50e1-42d2-b449-3f704dddc348" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_dd6bdad4-50e1-42d2-b449-3f704dddc348_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_dd6bdad4-50e1-42d2-b449-3f704dddc348" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range01Member_f533c681-0744-4de4-8a8f-e4508c741c0d" xlink:href="sfnc-20210930.xsd#sfnc_Range01Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range01Member_f533c681-0744-4de4-8a8f-e4508c741c0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range02Member_c8513239-e8a2-4917-989d-81eea7c755b3" xlink:href="sfnc-20210930.xsd#sfnc_Range02Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range02Member_c8513239-e8a2-4917-989d-81eea7c755b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range03Member_de57d633-51fa-4076-b4ed-d3e418fb7b01" xlink:href="sfnc-20210930.xsd#sfnc_Range03Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range03Member_de57d633-51fa-4076-b4ed-d3e418fb7b01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range04Member_0e72bf1b-b866-4128-a94c-30ea01a34738" xlink:href="sfnc-20210930.xsd#sfnc_Range04Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range04Member_0e72bf1b-b866-4128-a94c-30ea01a34738" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range05Member_97e1d32a-a504-429d-968d-f26be0a7e1a8" xlink:href="sfnc-20210930.xsd#sfnc_Range05Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range05Member_97e1d32a-a504-429d-968d-f26be0a7e1a8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range06Member_a69bb78f-ddfd-4432-b983-ec5c2c903899" xlink:href="sfnc-20210930.xsd#sfnc_Range06Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range06Member_a69bb78f-ddfd-4432-b983-ec5c2c903899" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range07Member_f1a33a26-21e7-419c-9260-a1998ddf6019" xlink:href="sfnc-20210930.xsd#sfnc_Range07Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range07Member_f1a33a26-21e7-419c-9260-a1998ddf6019" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_Range08Member_bc09f99e-e3a0-4a4e-95f5-0efcd311d896" xlink:href="sfnc-20210930.xsd#sfnc_Range08Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_5acf99b0-7363-4c19-aee7-e63099ad3fd5" xlink:to="loc_sfnc_Range08Member_bc09f99e-e3a0-4a4e-95f5-0efcd311d896" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/StockBasedCompensationSummaryofCompanysRestrictedPerformanceStockUnitActivityDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#StockBasedCompensationSummaryofCompanysRestrictedPerformanceStockUnitActivityDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/StockBasedCompensationSummaryofCompanysRestrictedPerformanceStockUnitActivityDetails" xlink:type="extended" id="ibc34b38ccf624fdeb7ea83796e547b2f_StockBasedCompensationSummaryofCompanysRestrictedPerformanceStockUnitActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0194cc6e-0686-4b00-8709-e5a250236b91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0194cc6e-0686-4b00-8709-e5a250236b91" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b8eb9b8a-a5ea-44bc-b1f5-1a965b6912d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b8eb9b8a-a5ea-44bc-b1f5-1a965b6912d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a9716d4c-7623-47a7-8475-3d8c4c98e8bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a9716d4c-7623-47a7-8475-3d8c4c98e8bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7f0d908d-8e01-4820-809c-a7ff05eb9104" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7f0d908d-8e01-4820-809c-a7ff05eb9104" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_92f8841e-950e-44fd-8944-3c2a225061b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_29934521-ac64-4013-b022-5e6a7409e818" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_359007c5-69c5-4967-a0b0-bc910a166c0b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_29934521-ac64-4013-b022-5e6a7409e818" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_9fec2538-88f5-4f61-b1f7-85dc36282375" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_29934521-ac64-4013-b022-5e6a7409e818" xlink:to="loc_us-gaap_AwardTypeAxis_9fec2538-88f5-4f61-b1f7-85dc36282375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9fec2538-88f5-4f61-b1f7-85dc36282375_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_9fec2538-88f5-4f61-b1f7-85dc36282375" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9fec2538-88f5-4f61-b1f7-85dc36282375_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_406b2ba3-102d-4969-9b4a-330e0568da4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_9fec2538-88f5-4f61-b1f7-85dc36282375" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_406b2ba3-102d-4969-9b4a-330e0568da4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_eb36169b-485e-4011-a7cd-9b1236707340" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_406b2ba3-102d-4969-9b4a-330e0568da4b" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_eb36169b-485e-4011-a7cd-9b1236707340" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/EarningsPerShareEPSTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#EarningsPerShareEPSTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/EarningsPerShareEPSTextualDetails" xlink:type="extended" id="ia7693949c19c41829024e5913cd53d19_EarningsPerShareEPSTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aa6697c1-ad2a-4b3f-9cb6-0ce5db13173e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3cda7c12-edfa-4ac1-88c6-9d081e5db71b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aa6697c1-ad2a-4b3f-9cb6-0ce5db13173e" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3cda7c12-edfa-4ac1-88c6-9d081e5db71b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_6161fc2a-967c-4fde-87b0-cbb1b31b4f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aa6697c1-ad2a-4b3f-9cb6-0ce5db13173e" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_6161fc2a-967c-4fde-87b0-cbb1b31b4f7b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_b9d082bd-623c-4964-9256-a452ed7d32e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_6161fc2a-967c-4fde-87b0-cbb1b31b4f7b" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_b9d082bd-623c-4964-9256-a452ed7d32e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_b9d082bd-623c-4964-9256-a452ed7d32e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_b9d082bd-623c-4964-9256-a452ed7d32e0" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_b9d082bd-623c-4964-9256-a452ed7d32e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_edc6ccd2-aea6-490e-b65f-bf50bb508e40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_b9d082bd-623c-4964-9256-a452ed7d32e0" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_edc6ccd2-aea6-490e-b65f-bf50bb508e40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_9cd1b668-38ea-4b9f-81aa-5ed11504628e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_edc6ccd2-aea6-490e-b65f-bf50bb508e40" xlink:to="loc_us-gaap_EmployeeStockOptionMember_9cd1b668-38ea-4b9f-81aa-5ed11504628e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/AdditionalCashFlowInformationDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#AdditionalCashFlowInformationDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/AdditionalCashFlowInformationDetails" xlink:type="extended" id="i2ff9a29d6a3a48b299a1cdda8d44814a_AdditionalCashFlowInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherSignificantNoncashTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_3e16cdfa-34b6-4c7e-a26a-8c6f92941a1e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_InterestPaidNet_3e16cdfa-34b6-4c7e-a26a-8c6f92941a1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet_8a40fdf5-969f-481a-9aa9-ee92a23e3b18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_IncomeTaxesPaidNet_8a40fdf5-969f-481a-9aa9-ee92a23e3b18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferToOtherRealEstate_cbecaf3c-58f3-42a0-bf53-b828c50d78e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferToOtherRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_TransferToOtherRealEstate_cbecaf3c-58f3-42a0-bf53-b828c50d78e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransferOfPropertyToHeldForSale_560c8ef0-e05c-4b26-9f2a-efae7c5c1cae" xlink:href="sfnc-20210930.xsd#sfnc_TransferOfPropertyToHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_sfnc_TransferOfPropertyToHeldForSale_560c8ef0-e05c-4b26-9f2a-efae7c5c1cae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransfersOfOtherRealEstateOwnedToPremisesHeldForSale_e6958455-6172-40ca-90fe-9a561ae4cf1e" xlink:href="sfnc-20210930.xsd#sfnc_TransfersOfOtherRealEstateOwnedToPremisesHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_sfnc_TransfersOfOtherRealEstateOwnedToPremisesHeldForSale_e6958455-6172-40ca-90fe-9a561ae4cf1e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferOfOtherRealEstate_661b73b7-00dd-4b29-9f4f-a0ab764d57d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferOfOtherRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_TransferOfOtherRealEstate_661b73b7-00dd-4b29-9f4f-a0ab764d57d0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransfersOfPremisesHeldForSaleToPremises_a3d7a76e-ba7e-4930-95d1-9498e590a408" xlink:href="sfnc-20210930.xsd#sfnc_TransfersOfPremisesHeldForSaleToPremises"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_sfnc_TransfersOfPremisesHeldForSaleToPremises_a3d7a76e-ba7e-4930-95d1-9498e590a408" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableReclassificationToHeldForSale_f0c0b695-f070-42eb-a929-ac365e15dbec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableReclassificationToHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_FinancingReceivableReclassificationToHeldForSale_f0c0b695-f070-42eb-a929-ac365e15dbec" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransferofDepositstoOtherLiabilitiesHeldforsale_68b2f5cb-4f41-4e60-ba52-1674a98d567b" xlink:href="sfnc-20210930.xsd#sfnc_TransferofDepositstoOtherLiabilitiesHeldforsale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_sfnc_TransferofDepositstoOtherLiabilitiesHeldforsale_68b2f5cb-4f41-4e60-ba52-1674a98d567b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherSignificantNoncashTransactionsTable_256e170c-fc5b-4829-8f19-056a986abae2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherSignificantNoncashTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsLineItems_c2e307a4-3c8f-463c-8b50-8d47af48deba" xlink:to="loc_us-gaap_OtherSignificantNoncashTransactionsTable_256e170c-fc5b-4829-8f19-056a986abae2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis_fcf9e782-2adf-41a8-99d1-1ca7d6536f33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsTable_256e170c-fc5b-4829-8f19-056a986abae2" xlink:to="loc_us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis_fcf9e782-2adf-41a8-99d1-1ca7d6536f33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_fcf9e782-2adf-41a8-99d1-1ca7d6536f33_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherSignificantNoncashTransactionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis_fcf9e782-2adf-41a8-99d1-1ca7d6536f33" xlink:to="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_fcf9e782-2adf-41a8-99d1-1ca7d6536f33_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_2f6d38e6-3f56-461c-83fa-104add92de3a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherSignificantNoncashTransactionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis_fcf9e782-2adf-41a8-99d1-1ca7d6536f33" xlink:to="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_2f6d38e6-3f56-461c-83fa-104add92de3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransfersofLoanstoForeclosedAssetsHeldforSaleMember_667e1d88-a471-409e-b64b-c425133cc1f9" xlink:href="sfnc-20210930.xsd#sfnc_TransfersofLoanstoForeclosedAssetsHeldforSaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_2f6d38e6-3f56-461c-83fa-104add92de3a" xlink:to="loc_sfnc_TransfersofLoanstoForeclosedAssetsHeldforSaleMember_667e1d88-a471-409e-b64b-c425133cc1f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TransferOfPremisesToForeclosedAssetsAndOtherRealEstateOwnedMember_5d5b554e-10a4-46be-b8e6-0d7428aa941f" xlink:href="sfnc-20210930.xsd#sfnc_TransferOfPremisesToForeclosedAssetsAndOtherRealEstateOwnedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherSignificantNoncashTransactionNameDomain_2f6d38e6-3f56-461c-83fa-104add92de3a" xlink:to="loc_sfnc_TransferOfPremisesToForeclosedAssetsAndOtherRealEstateOwnedMember_5d5b554e-10a4-46be-b8e6-0d7428aa941f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/CommitmentsandCreditRiskTextualDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#CommitmentsandCreditRiskTextualDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/CommitmentsandCreditRiskTextualDetails" xlink:type="extended" id="iec33685e33b44102a353b5911461e739_CommitmentsandCreditRiskTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusedCommitmentsToExtendCredit_f56aabb5-149a-4391-9a4e-ff2d42766555" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusedCommitmentsToExtendCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:to="loc_us-gaap_UnusedCommitmentsToExtendCredit_f56aabb5-149a-4391-9a4e-ff2d42766555" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_aeedba19-c875-460d-91c0-52ff25900ce0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_aeedba19-c875-460d-91c0-52ff25900ce0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_LettersOfCreditTerm_a5a0e846-7e52-4af0-985c-45584d07e3e6" xlink:href="sfnc-20210930.xsd#sfnc_LettersOfCreditTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:to="loc_sfnc_LettersOfCreditTerm_a5a0e846-7e52-4af0-985c-45584d07e3e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_76cdb785-b9b4-4e9e-87fa-2f1f627d5b99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:to="loc_us-gaap_ContractWithCustomerLiability_76cdb785-b9b4-4e9e-87fa-2f1f627d5b99" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_634466cd-a8a8-4496-a678-533252e50a59" xlink:to="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_6aa70014-64d9-4854-bd31-5074a9bfe86c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:to="loc_us-gaap_FinancialInstrumentAxis_6aa70014-64d9-4854-bd31-5074a9bfe86c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6aa70014-64d9-4854-bd31-5074a9bfe86c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_6aa70014-64d9-4854-bd31-5074a9bfe86c" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6aa70014-64d9-4854-bd31-5074a9bfe86c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e98cfb46-b15e-42c2-9fb1-9443dfc8f7d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_6aa70014-64d9-4854-bd31-5074a9bfe86c" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e98cfb46-b15e-42c2-9fb1-9443dfc8f7d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_CreditCardCommitmentsToExtendCreditMember_b6c7684b-ac74-4739-b38a-f5fe0a4ab11f" xlink:href="sfnc-20210930.xsd#sfnc_CreditCardCommitmentsToExtendCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e98cfb46-b15e-42c2-9fb1-9443dfc8f7d3" xlink:to="loc_sfnc_CreditCardCommitmentsToExtendCreditMember_b6c7684b-ac74-4739-b38a-f5fe0a4ab11f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherLoanCommitmentsToExtendCreditMember_82d9b055-5046-488e-943f-cb6f3818183f" xlink:href="sfnc-20210930.xsd#sfnc_OtherLoanCommitmentsToExtendCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e98cfb46-b15e-42c2-9fb1-9443dfc8f7d3" xlink:to="loc_sfnc_OtherLoanCommitmentsToExtendCreditMember_82d9b055-5046-488e-943f-cb6f3818183f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_FixedRateMortgageLoansMember_7fe38ab3-48ae-4535-bbd1-2dcee32604b4" xlink:href="sfnc-20210930.xsd#sfnc_FixedRateMortgageLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e98cfb46-b15e-42c2-9fb1-9443dfc8f7d3" xlink:to="loc_sfnc_FixedRateMortgageLoansMember_7fe38ab3-48ae-4535-bbd1-2dcee32604b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:to="loc_srt_RangeAxis_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c" xlink:to="loc_srt_RangeMember_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2e20b028-244c-4100-bf9e-ec0c19ee6f1e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_f20778d5-d9a6-4e0a-bf09-5b69f8dfe64c" xlink:to="loc_srt_RangeMember_2e20b028-244c-4100-bf9e-ec0c19ee6f1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0449a35b-10b1-4382-87a1-e2de8eb4b9e9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2e20b028-244c-4100-bf9e-ec0c19ee6f1e" xlink:to="loc_srt_MinimumMember_0449a35b-10b1-4382-87a1-e2de8eb4b9e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6d1e6e99-9133-474a-9df5-74372cd43bd6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2e20b028-244c-4100-bf9e-ec0c19ee6f1e" xlink:to="loc_srt_MaximumMember_6d1e6e99-9133-474a-9df5-74372cd43bd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeAxis_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeAxis_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeDomain_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeAxis_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeDomain_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeDomain_267b4e90-5e03-4e6c-869a-a9dbe363fc32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeAxis_06cabb09-12ba-4f2a-9ce2-01a5ba3673aa" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeDomain_267b4e90-5e03-4e6c-869a-a9dbe363fc32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_StandbyLettersOfCredit1Member_7884e872-8123-4cea-9d99-ef3683d2b034" xlink:href="sfnc-20210930.xsd#sfnc_StandbyLettersOfCredit1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeDomain_267b4e90-5e03-4e6c-869a-a9dbe363fc32" xlink:to="loc_sfnc_StandbyLettersOfCredit1Member_7884e872-8123-4cea-9d99-ef3683d2b034" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_0190fa7c-3f81-467e-899b-98f6b1013914" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_3c4a23d1-c37a-42a9-8e21-eeb138578328" xlink:to="loc_us-gaap_InvestmentTypeAxis_0190fa7c-3f81-467e-899b-98f6b1013914" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_0190fa7c-3f81-467e-899b-98f6b1013914_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_0190fa7c-3f81-467e-899b-98f6b1013914" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_0190fa7c-3f81-467e-899b-98f6b1013914_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_b58fc1fc-dbcd-4294-aa17-2524b3f105ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_0190fa7c-3f81-467e-899b-98f6b1013914" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_b58fc1fc-dbcd-4294-aa17-2524b3f105ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankCertificatesAndObligationsFHLBMember_70993653-90e8-4430-93d3-c5b2d77f1916" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalHomeLoanBankCertificatesAndObligationsFHLBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_b58fc1fc-dbcd-4294-aa17-2524b3f105ba" xlink:to="loc_us-gaap_FederalHomeLoanBankCertificatesAndObligationsFHLBMember_70993653-90e8-4430-93d3-c5b2d77f1916" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/FairValueMeasurementsFairValueofFinancialAssetsMeasureonaRecurringBasisDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#FairValueMeasurementsFairValueofFinancialAssetsMeasureonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/FairValueMeasurementsFairValueofFinancialAssetsMeasureonaRecurringBasisDetails" xlink:type="extended" id="i99cd1b82498340fd895fef7c4cb6875a_FairValueMeasurementsFairValueofFinancialAssetsMeasureonaRecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_dfe112d2-6770-452f-9cb5-24b6cbf88585" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_dfe112d2-6770-452f-9cb5-24b6cbf88585" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesHeldForSaleFairValueDisclosure_41144f82-1b4a-44a2-bc09-0e49b24a3f97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgagesHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_us-gaap_MortgagesHeldForSaleFairValueDisclosure_41144f82-1b4a-44a2-bc09-0e49b24a3f97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_1f2b920c-c863-47c5-9b50-0325e5a6dc60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_us-gaap_DerivativeAssets_1f2b920c-c863-47c5-9b50-0325e5a6dc60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherLiabilitiesHeldForSaleFairValueDisclosure_a842502a-3dbc-4b9c-a8bc-cf5c687b7145" xlink:href="sfnc-20210930.xsd#sfnc_OtherLiabilitiesHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_sfnc_OtherLiabilitiesHeldForSaleFairValueDisclosure_a842502a-3dbc-4b9c-a8bc-cf5c687b7145" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_1499d44c-fce0-4df4-97bf-00fb45b9c81d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_us-gaap_DerivativeLiabilities_1499d44c-fce0-4df4-97bf-00fb45b9c81d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_98f00a3c-6320-48e2-9e83-d2769a4c1ee1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_1bfa9f54-8ae6-4afe-816b-ff79c0279fb9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_98f00a3c-6320-48e2-9e83-d2769a4c1ee1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_92cfa789-2b2e-42ed-b806-3dd970836242" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_98f00a3c-6320-48e2-9e83-d2769a4c1ee1" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_92cfa789-2b2e-42ed-b806-3dd970836242" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_92cfa789-2b2e-42ed-b806-3dd970836242_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_92cfa789-2b2e-42ed-b806-3dd970836242" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_92cfa789-2b2e-42ed-b806-3dd970836242_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_9c9d4945-1bf6-4734-9290-78b09866bfdc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_92cfa789-2b2e-42ed-b806-3dd970836242" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_9c9d4945-1bf6-4734-9290-78b09866bfdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_c5381bb6-b3d0-47a3-a0b5-67098576a81f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_9c9d4945-1bf6-4734-9290-78b09866bfdc" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_c5381bb6-b3d0-47a3-a0b5-67098576a81f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_98f00a3c-6320-48e2-9e83-d2769a4c1ee1" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ce6e762-1d13-4f6c-90af-431e508b19bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238e0fc2-7c1f-4b28-bf2f-e409a67d2dfb" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ce6e762-1d13-4f6c-90af-431e508b19bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_06bf9a6e-6376-411f-bea0-7b3e172b757d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ce6e762-1d13-4f6c-90af-431e508b19bf" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_06bf9a6e-6376-411f-bea0-7b3e172b757d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_7de699b2-1786-4075-98f9-72b1b3f68f4d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ce6e762-1d13-4f6c-90af-431e508b19bf" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_7de699b2-1786-4075-98f9-72b1b3f68f4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_ab1d3199-d2e6-4a0b-a576-9d7a50a13d1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ce6e762-1d13-4f6c-90af-431e508b19bf" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_ab1d3199-d2e6-4a0b-a576-9d7a50a13d1c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_4c0b33bf-224c-4b97-8d86-f7c6018fd17a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_98f00a3c-6320-48e2-9e83-d2769a4c1ee1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_4c0b33bf-224c-4b97-8d86-f7c6018fd17a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4c0b33bf-224c-4b97-8d86-f7c6018fd17a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_4c0b33bf-224c-4b97-8d86-f7c6018fd17a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4c0b33bf-224c-4b97-8d86-f7c6018fd17a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_4c0b33bf-224c-4b97-8d86-f7c6018fd17a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_378d3e4b-75cb-4fba-b447-953cd85f8d33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_378d3e4b-75cb-4fba-b447-953cd85f8d33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_b63e452e-4399-4e99-99aa-ccc78fa0cbd9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_b63e452e-4399-4e99-99aa-ccc78fa0cbd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_46dc8909-2bf4-4c14-bb31-e5bd68d87999" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember_46dc8909-2bf4-4c14-bb31-e5bd68d87999" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_ee0653ec-32b5-4e5d-80d0-3c1ecfcdaf56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_ee0653ec-32b5-4e5d-80d0-3c1ecfcdaf56" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherSecuritiesMember_13b48b39-50ef-491d-8c22-f9af4d84351b" xlink:href="sfnc-20210930.xsd#sfnc_OtherSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f2b969e-1603-493d-a2a8-e49994ef2449" xlink:to="loc_sfnc_OtherSecuritiesMember_13b48b39-50ef-491d-8c22-f9af4d84351b" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/FairValueMeasurementsFairValueofFinancialAssetsMeasuredonaNonrecurringBasisDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#FairValueMeasurementsFairValueofFinancialAssetsMeasuredonaNonrecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/FairValueMeasurementsFairValueofFinancialAssetsMeasuredonaNonrecurringBasisDetails" xlink:type="extended" id="ia7b761586a954daba8186d71bbbb4a4f_FairValueMeasurementsFairValueofFinancialAssetsMeasuredonaNonrecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8ab17d5-61a4-4272-b92c-867254a6529f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_ImpairedFinancingReceivableRecordedInvestmentFairValueDisclosure_8725e28b-fcef-4fdd-ad97-b33a769bcdf3" xlink:href="sfnc-20210930.xsd#sfnc_ImpairedFinancingReceivableRecordedInvestmentFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8ab17d5-61a4-4272-b92c-867254a6529f" xlink:to="loc_sfnc_ImpairedFinancingReceivableRecordedInvestmentFairValueDisclosure_8725e28b-fcef-4fdd-ad97-b33a769bcdf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_d07cbeb3-4f00-46c4-81cc-ef86a76180b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8ab17d5-61a4-4272-b92c-867254a6529f" xlink:to="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_d07cbeb3-4f00-46c4-81cc-ef86a76180b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7cc30320-3ccd-4019-89b9-88a610f52ed4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8ab17d5-61a4-4272-b92c-867254a6529f" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7cc30320-3ccd-4019-89b9-88a610f52ed4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_af3f49b8-8506-49c8-9ee9-6b2b4379fa7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_e8ab17d5-61a4-4272-b92c-867254a6529f" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_af3f49b8-8506-49c8-9ee9-6b2b4379fa7b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_4b2345f9-92b5-49dd-b54f-f6c086fc7b57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_af3f49b8-8506-49c8-9ee9-6b2b4379fa7b" xlink:to="loc_us-gaap_CollateralAxis_4b2345f9-92b5-49dd-b54f-f6c086fc7b57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_4b2345f9-92b5-49dd-b54f-f6c086fc7b57_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_4b2345f9-92b5-49dd-b54f-f6c086fc7b57" xlink:to="loc_us-gaap_CollateralDomain_4b2345f9-92b5-49dd-b54f-f6c086fc7b57_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_4f77447e-94e6-4d4b-bc82-f519429a0b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_4b2345f9-92b5-49dd-b54f-f6c086fc7b57" xlink:to="loc_us-gaap_CollateralDomain_4f77447e-94e6-4d4b-bc82-f519429a0b2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralPledgedMember_53e794c8-62ff-4ddd-b46e-e30afbf8c339" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralPledgedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_4f77447e-94e6-4d4b-bc82-f519429a0b2c" xlink:to="loc_us-gaap_CollateralPledgedMember_53e794c8-62ff-4ddd-b46e-e30afbf8c339" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44677bc0-8345-4f42-983f-371de8277152" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_af3f49b8-8506-49c8-9ee9-6b2b4379fa7b" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44677bc0-8345-4f42-983f-371de8277152" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_44677bc0-8345-4f42-983f-371de8277152_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44677bc0-8345-4f42-983f-371de8277152" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_44677bc0-8345-4f42-983f-371de8277152_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1ba4ccc7-237c-4473-8a0f-dbd8a8b9e23f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_44677bc0-8345-4f42-983f-371de8277152" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1ba4ccc7-237c-4473-8a0f-dbd8a8b9e23f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_8e9ec390-8ec9-4074-9149-35fa7d067cec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1ba4ccc7-237c-4473-8a0f-dbd8a8b9e23f" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_8e9ec390-8ec9-4074-9149-35fa7d067cec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_28e31097-3711-46cf-9f48-c6f3c84af83b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1ba4ccc7-237c-4473-8a0f-dbd8a8b9e23f" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_28e31097-3711-46cf-9f48-c6f3c84af83b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_95030c95-dec3-4c28-998c-69f9b8fd29e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1ba4ccc7-237c-4473-8a0f-dbd8a8b9e23f" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_95030c95-dec3-4c28-998c-69f9b8fd29e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_078e41e3-d521-4b7a-8cc6-75d417b35540" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_af3f49b8-8506-49c8-9ee9-6b2b4379fa7b" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_078e41e3-d521-4b7a-8cc6-75d417b35540" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_078e41e3-d521-4b7a-8cc6-75d417b35540_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_078e41e3-d521-4b7a-8cc6-75d417b35540" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_078e41e3-d521-4b7a-8cc6-75d417b35540_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_a9f463fc-eeae-4ca4-b39c-1955b7c226b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_078e41e3-d521-4b7a-8cc6-75d417b35540" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_a9f463fc-eeae-4ca4-b39c-1955b7c226b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_3a3cdfa8-3ada-414c-a1c8-0def154212f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_a9f463fc-eeae-4ca4-b39c-1955b7c226b8" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_3a3cdfa8-3ada-414c-a1c8-0def154212f4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/FairValueMeasurementsEstimatedFairValuesandRelatedCarryingAmountsofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#FairValueMeasurementsEstimatedFairValuesandRelatedCarryingAmountsofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/FairValueMeasurementsEstimatedFairValuesandRelatedCarryingAmountsofFinancialInstrumentsDetails" xlink:type="extended" id="icd2587b92e3b427682ad602b6dcfac20_FairValueMeasurementsEstimatedFairValuesandRelatedCarryingAmountsofFinancialInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_1198c7fb-b221-42ce-a737-ae52cbd6ea8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_1198c7fb-b221-42ce-a737-ae52cbd6ea8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestBearingBalancesDueFromBanksTimeFairValueDisclosure_0ab8c694-6df9-4887-8c87-ca0079989ce9" xlink:href="sfnc-20210930.xsd#sfnc_InterestBearingBalancesDueFromBanksTimeFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_sfnc_InterestBearingBalancesDueFromBanksTimeFairValueDisclosure_0ab8c694-6df9-4887-8c87-ca0079989ce9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_3be0dbac-db86-4856-9b17-55f19dc09700" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_3be0dbac-db86-4856-9b17-55f19dc09700" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestReceivableFairValueDisclosure_17997e9a-7906-45f3-87df-1c23e084906d" xlink:href="sfnc-20210930.xsd#sfnc_InterestReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_sfnc_InterestReceivableFairValueDisclosure_17997e9a-7906-45f3-87df-1c23e084906d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_4e1361ef-e951-42b5-a7cb-7341781f588b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_4e1361ef-e951-42b5-a7cb-7341781f588b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_e53de7ed-c218-49a9-b6ff-617d829d5f97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepositsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_e53de7ed-c218-49a9-b6ff-617d829d5f97" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_bc191258-cd65-4f27-a749-209228180f89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_bc191258-cd65-4f27-a749-209228180f89" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_OtherBorrowingsFairValueDisclosure_ec6d6744-b450-4e62-bdeb-c6c547f76a31" xlink:href="sfnc-20210930.xsd#sfnc_OtherBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_sfnc_OtherBorrowingsFairValueDisclosure_ec6d6744-b450-4e62-bdeb-c6c547f76a31" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_e0a146a8-c9e0-4907-af12-e23404bfd084" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_e0a146a8-c9e0-4907-af12-e23404bfd084" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestPayableFairValueDisclosure_c6313d76-5c7d-44cf-ada2-af941ed81f42" xlink:href="sfnc-20210930.xsd#sfnc_InterestPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_sfnc_InterestPayableFairValueDisclosure_c6313d76-5c7d-44cf-ada2-af941ed81f42" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_29a5e3e5-ff82-472e-926e-56fd6843849e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_be644148-4b7d-49f4-a36d-ee5865ceac7b" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_29a5e3e5-ff82-472e-926e-56fd6843849e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_d19a936e-763a-4815-8fc9-7918f0541943" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_29a5e3e5-ff82-472e-926e-56fd6843849e" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_d19a936e-763a-4815-8fc9-7918f0541943" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_d19a936e-763a-4815-8fc9-7918f0541943_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_d19a936e-763a-4815-8fc9-7918f0541943" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_d19a936e-763a-4815-8fc9-7918f0541943_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2a99db9f-c033-4b51-9580-4f06ab8dd038" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_d19a936e-763a-4815-8fc9-7918f0541943" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2a99db9f-c033-4b51-9580-4f06ab8dd038" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_2dd3d6dd-b209-4505-8e51-8e2c1b25890c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2a99db9f-c033-4b51-9580-4f06ab8dd038" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_2dd3d6dd-b209-4505-8e51-8e2c1b25890c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_cceac18f-5085-4a2b-ae2c-6b8a3e50b4b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2a99db9f-c033-4b51-9580-4f06ab8dd038" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_cceac18f-5085-4a2b-ae2c-6b8a3e50b4b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8a00bf72-4b67-456c-ba55-84d883d71359" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2a99db9f-c033-4b51-9580-4f06ab8dd038" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8a00bf72-4b67-456c-ba55-84d883d71359" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ff4a91da-ec29-4572-98dc-df8ad02a8754" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_29a5e3e5-ff82-472e-926e-56fd6843849e" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ff4a91da-ec29-4572-98dc-df8ad02a8754" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ff4a91da-ec29-4572-98dc-df8ad02a8754_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ff4a91da-ec29-4572-98dc-df8ad02a8754" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ff4a91da-ec29-4572-98dc-df8ad02a8754_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9c788c6a-d25e-4b57-acb9-c930bc9dfa19" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ff4a91da-ec29-4572-98dc-df8ad02a8754" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9c788c6a-d25e-4b57-acb9-c930bc9dfa19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_dd99cf2b-bfc7-4fe6-8758-5b62065d4e21" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9c788c6a-d25e-4b57-acb9-c930bc9dfa19" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_dd99cf2b-bfc7-4fe6-8758-5b62065d4e21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_109d46c4-955f-479b-a771-6f1ef4122cb7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9c788c6a-d25e-4b57-acb9-c930bc9dfa19" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_109d46c4-955f-479b-a771-6f1ef4122cb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_b5e6702c-cf84-4401-97c1-691902206817" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9c788c6a-d25e-4b57-acb9-c930bc9dfa19" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_b5e6702c-cf84-4401-97c1-691902206817" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_abeec19a-92fe-4caa-add1-21ec15cfc74f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_29a5e3e5-ff82-472e-926e-56fd6843849e" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_abeec19a-92fe-4caa-add1-21ec15cfc74f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_abeec19a-92fe-4caa-add1-21ec15cfc74f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_abeec19a-92fe-4caa-add1-21ec15cfc74f" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_abeec19a-92fe-4caa-add1-21ec15cfc74f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3f49879e-6e5d-4936-b91f-be93ec540d1d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_abeec19a-92fe-4caa-add1-21ec15cfc74f" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3f49879e-6e5d-4936-b91f-be93ec540d1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_NonInterestBearingTransactionAccountsMember_d7638d5e-fc45-4c0a-a9f1-1758b0c80615" xlink:href="sfnc-20210930.xsd#sfnc_NonInterestBearingTransactionAccountsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3f49879e-6e5d-4936-b91f-be93ec540d1d" xlink:to="loc_sfnc_NonInterestBearingTransactionAccountsMember_d7638d5e-fc45-4c0a-a9f1-1758b0c80615" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_InterestBearingTransactionAccountsAndSavingsDepositsMember_3f10f990-d7ae-4b11-b459-31a78eaed5aa" xlink:href="sfnc-20210930.xsd#sfnc_InterestBearingTransactionAccountsAndSavingsDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3f49879e-6e5d-4936-b91f-be93ec540d1d" xlink:to="loc_sfnc_InterestBearingTransactionAccountsAndSavingsDepositsMember_3f10f990-d7ae-4b11-b459-31a78eaed5aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_TimeDepositsMember_6bb899bd-5881-48a1-bb16-aac922eacb2d" xlink:href="sfnc-20210930.xsd#sfnc_TimeDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3f49879e-6e5d-4936-b91f-be93ec540d1d" xlink:to="loc_sfnc_TimeDepositsMember_6bb899bd-5881-48a1-bb16-aac922eacb2d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/DerivativeInstrumentsDerivativeInstrumentsNotionalandFairValueAmountsofDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#DerivativeInstrumentsDerivativeInstrumentsNotionalandFairValueAmountsofDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/DerivativeInstrumentsDerivativeInstrumentsNotionalandFairValueAmountsofDerivativeInstrumentsDetails" xlink:type="extended" id="ia29244439b1e4cf49e9e409a9ba9b1ce_DerivativeInstrumentsDerivativeInstrumentsNotionalandFairValueAmountsofDerivativeInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAverageVariableInterestRate_74f05ac2-0314-4a9c-8b09-1331fc1b83fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAverageVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_DerivativeAverageVariableInterestRate_74f05ac2-0314-4a9c-8b09-1331fc1b83fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetNotionalAmount_421e8028-5388-4936-8ec4-cd56fc472bdd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_DerivativeAssetNotionalAmount_421e8028-5388-4936-8ec4-cd56fc472bdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_1005d2f8-dc5e-47a7-9719-4fca47c07158" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_DerivativeAssets_1005d2f8-dc5e-47a7-9719-4fca47c07158" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_94e74466-53b7-4b03-8e7a-e88b7a4bc332" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_94e74466-53b7-4b03-8e7a-e88b7a4bc332" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_57f0f7e5-2fe9-47ec-b813-12e8cdaf3d23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_DerivativeLiabilities_57f0f7e5-2fe9-47ec-b813-12e8cdaf3d23" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_f004da75-b7be-479b-a052-8ff9cb096fa3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_93dd8d67-3a8c-40cc-bd7a-cee5f50e20f5" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_f004da75-b7be-479b-a052-8ff9cb096fa3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_f004da75-b7be-479b-a052-8ff9cb096fa3" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_600f38ed-ccbb-45fc-8036-e51b52b2eb9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b1a4b99c-3b31-47a5-8fc1-99a4ba2d417b" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_600f38ed-ccbb-45fc-8036-e51b52b2eb9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgingMember_642047b3-22bc-498c-9140-766f87fda3db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_600f38ed-ccbb-45fc-8036-e51b52b2eb9a" xlink:to="loc_us-gaap_FairValueHedgingMember_642047b3-22bc-498c-9140-766f87fda3db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6082e735-ad4c-4f33-a373-fc58b218d514" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_600f38ed-ccbb-45fc-8036-e51b52b2eb9a" xlink:to="loc_us-gaap_InterestRateSwapMember_6082e735-ad4c-4f33-a373-fc58b218d514" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://simmonsbank.com/role/DerivativeInstrumentsNarrativeDetails" xlink:type="simple" xlink:href="sfnc-20210930.xsd#DerivativeInstrumentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://simmonsbank.com/role/DerivativeInstrumentsNarrativeDetails" xlink:type="extended" id="iac3b3076e58e468599d325f57abbbbea_DerivativeInstrumentsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_DerivativeInstrumentCovenantMaximumOutstandingNotionalContractAmountPercentOfAssets_620143e3-edea-4ee2-a26c-82976d81af02" xlink:href="sfnc-20210930.xsd#sfnc_DerivativeInstrumentCovenantMaximumOutstandingNotionalContractAmountPercentOfAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_sfnc_DerivativeInstrumentCovenantMaximumOutstandingNotionalContractAmountPercentOfAssets_620143e3-edea-4ee2-a26c-82976d81af02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_da30a84d-eac1-4e70-bedc-2493a659333a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_us-gaap_DerivativeNotionalAmount_da30a84d-eac1-4e70-bedc-2493a659333a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetNotionalAmount_d4686990-84d4-4bcf-b09f-53adf3016885" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_us-gaap_DerivativeAssetNotionalAmount_d4686990-84d4-4bcf-b09f-53adf3016885" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_a355b771-e9bf-4dee-9c69-5d3629746ecc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_a355b771-e9bf-4dee-9c69-5d3629746ecc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_a9964803-c16f-4afb-b100-353ebb57a691" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_a9964803-c16f-4afb-b100-353ebb57a691" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_761e2b26-6864-418d-8fbb-ad969877c138" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_a88c8ab9-7d0c-433f-b969-86a72941801f" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_761e2b26-6864-418d-8fbb-ad969877c138" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_bde6559b-3739-47d6-a816-6e99e7cc5045" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_761e2b26-6864-418d-8fbb-ad969877c138" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_bde6559b-3739-47d6-a816-6e99e7cc5045" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_bde6559b-3739-47d6-a816-6e99e7cc5045_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_bde6559b-3739-47d6-a816-6e99e7cc5045" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_bde6559b-3739-47d6-a816-6e99e7cc5045_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5509dbc1-8db2-4579-9741-436686256036" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_bde6559b-3739-47d6-a816-6e99e7cc5045" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5509dbc1-8db2-4579-9741-436686256036" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sfnc_RiskParticipationAgreementsMember_59107843-eaac-42e1-ad1f-d09da50bd9bf" xlink:href="sfnc-20210930.xsd#sfnc_RiskParticipationAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5509dbc1-8db2-4579-9741-436686256036" xlink:to="loc_sfnc_RiskParticipationAgreementsMember_59107843-eaac-42e1-ad1f-d09da50bd9bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnergyRelatedDerivativeMember_63cc28c6-bc97-4540-ac67-b68403649945" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnergyRelatedDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5509dbc1-8db2-4579-9741-436686256036" xlink:to="loc_us-gaap_EnergyRelatedDerivativeMember_63cc28c6-bc97-4540-ac67-b68403649945" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-roles-2021-01-31.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
