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

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:cbc5e4f4-a5cf-4cd7-9e77-2f3acab88ac0,g:c886f0b9-fa14-42f2-91e7-6b4a395bcd32-->
<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://www.shattucklabs.com/role/STATEMENTOFCHANGESINREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT" xlink:type="simple" xlink:href="sttk-20211231.xsd#STATEMENTOFCHANGESINREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/STATEMENTOFCHANGESINREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT" xlink:type="extended" id="ib69aee3838fe4399953927474b15a8ad_STATEMENTOFCHANGESINREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSEQUITYDEFICIT">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_dc78aaec-f4b5-4b40-886a-1f2e6221103f" 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_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_dc78aaec-f4b5-4b40-886a-1f2e6221103f" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_ba4648bf-1050-4749-99bb-8433d8ecc252" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_ba4648bf-1050-4749-99bb-8433d8ecc252" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_0bae7067-c59e-43e0-bc6b-e62cde0fb2bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_0bae7067-c59e-43e0-bc6b-e62cde0fb2bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_42f9461c-3ff9-4b52-968b-2d30bd5f0824" xlink:href="sttk-20211231.xsd#sttk_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_sttk_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_42f9461c-3ff9-4b52-968b-2d30bd5f0824" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_8c7f440a-3882-4bd5-8ce7-81528fee592d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_8c7f440a-3882-4bd5-8ce7-81528fee592d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_TemporaryEquitySharesConversionOfConvertibleSecuritiesIntoCommonStock_77059a5a-2a61-4e38-a780-f3dd7b5d47f9" xlink:href="sttk-20211231.xsd#sttk_TemporaryEquitySharesConversionOfConvertibleSecuritiesIntoCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_sttk_TemporaryEquitySharesConversionOfConvertibleSecuritiesIntoCommonStock_77059a5a-2a61-4e38-a780-f3dd7b5d47f9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_TemporaryEquityValueConversionOfConvertibleSecuritiesIntoCommonStock_7d33892a-e5d2-4304-a045-e5fac8488c58" xlink:href="sttk-20211231.xsd#sttk_TemporaryEquityValueConversionOfConvertibleSecuritiesIntoCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_d9f37e88-1b2e-454f-9487-608c84008f9d" xlink:to="loc_sttk_TemporaryEquityValueConversionOfConvertibleSecuritiesIntoCommonStock_7d33892a-e5d2-4304-a045-e5fac8488c58" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_8c98a71a-3b62-4b20-83f9-633d2483c9fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_0751e12a-e000-49b9-ac18-7c1c74279b80" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" 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_dc78aaec-f4b5-4b40-886a-1f2e6221103f" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_314e8b35-f71f-40c5-bf2d-f254ba81dd4e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_SharesOutstanding_314e8b35-f71f-40c5-bf2d-f254ba81dd4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6186481f-6931-4f41-aca8-b19b45fadff2" 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_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockholdersEquity_6186481f-6931-4f41-aca8-b19b45fadff2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_0f4531b6-e693-4ea6-82c3-ad8fec6e3365" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_0f4531b6-e693-4ea6-82c3-ad8fec6e3365" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_e8e815f5-cf87-40aa-8d91-b896037a6e1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_e8e815f5-cf87-40aa-8d91-b896037a6e1c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_05cafcab-6a20-4369-b485-d4d5b403dc85" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_05cafcab-6a20-4369-b485-d4d5b403dc85" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_af2d025b-bb7b-474f-82c0-a48b79fa99db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_af2d025b-bb7b-474f-82c0-a48b79fa99db" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_c95988de-6681-4b6d-8d1b-008b3ff07b50" 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_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_c95988de-6681-4b6d-8d1b-008b3ff07b50" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_f32ad2cf-0ecd-4099-ba42-864c585a4f32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_f32ad2cf-0ecd-4099-ba42-864c585a4f32" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_5f48f726-ba39-4df1-9591-2190ae757fe7" 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_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_5f48f726-ba39-4df1-9591-2190ae757fe7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d07d7a5b-4322-4176-a1f0-fdbf0148380b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d07d7a5b-4322-4176-a1f0-fdbf0148380b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_e5628606-75de-48c7-a743-4759517b2cee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_e5628606-75de-48c7-a743-4759517b2cee" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_8adfbcf2-b07c-410c-b54c-61eeca75eb0a" 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_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_us-gaap_NetIncomeLoss_8adfbcf2-b07c-410c-b54c-61eeca75eb0a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesAndESPPPurchasesInPeriod_520de38a-c115-4609-81f1-35618e74697b" xlink:href="sttk-20211231.xsd#sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesAndESPPPurchasesInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesAndESPPPurchasesInPeriod_520de38a-c115-4609-81f1-35618e74697b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_StockIssuedDuringPeriodValueStockOptionsExercisedAndESPPPurchased_985e8f43-7f42-4b25-8749-515954536df6" xlink:href="sttk-20211231.xsd#sttk_StockIssuedDuringPeriodValueStockOptionsExercisedAndESPPPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_03cf596b-7478-4100-94fd-2592553b531e" xlink:to="loc_sttk_StockIssuedDuringPeriodValueStockOptionsExercisedAndESPPPurchased_985e8f43-7f42-4b25-8749-515954536df6" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_77c75848-8408-4868-a2ea-de21f10ebf7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4c2fc93b-aaee-4c84-a2d4-1f2d0c052a0b" 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_StatementTable_86fe8e45-e63c-4417-9a3e-366b25405867" 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_dc78aaec-f4b5-4b40-886a-1f2e6221103f" xlink:to="loc_us-gaap_StatementTable_86fe8e45-e63c-4417-9a3e-366b25405867" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_e8090fad-67b9-4ea5-92bd-33efd5dc2330" 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_StatementTable_86fe8e45-e63c-4417-9a3e-366b25405867" xlink:to="loc_us-gaap_StatementClassOfStockAxis_e8090fad-67b9-4ea5-92bd-33efd5dc2330" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e8090fad-67b9-4ea5-92bd-33efd5dc2330_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_e8090fad-67b9-4ea5-92bd-33efd5dc2330" xlink:to="loc_us-gaap_ClassOfStockDomain_e8090fad-67b9-4ea5-92bd-33efd5dc2330_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_077b067c-94af-499a-bc23-753393919c49" 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_e8090fad-67b9-4ea5-92bd-33efd5dc2330" xlink:to="loc_us-gaap_ClassOfStockDomain_077b067c-94af-499a-bc23-753393919c49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_7203fbb0-4d78-4af3-90fa-21dca29ed398" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_077b067c-94af-499a-bc23-753393919c49" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_7203fbb0-4d78-4af3-90fa-21dca29ed398" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_8f3c7644-a8ff-4966-8500-2bb382218bcf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_077b067c-94af-499a-bc23-753393919c49" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_8f3c7644-a8ff-4966-8500-2bb382218bcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_SeriesB1PreferredStockMember_ee32d982-99aa-438b-8799-24b4f99de164" xlink:href="sttk-20211231.xsd#sttk_SeriesB1PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_077b067c-94af-499a-bc23-753393919c49" xlink:to="loc_sttk_SeriesB1PreferredStockMember_ee32d982-99aa-438b-8799-24b4f99de164" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9fb7fc97-13d3-499c-8ac3-1e63947c56c7" 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_86fe8e45-e63c-4417-9a3e-366b25405867" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9fb7fc97-13d3-499c-8ac3-1e63947c56c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9fb7fc97-13d3-499c-8ac3-1e63947c56c7_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_9fb7fc97-13d3-499c-8ac3-1e63947c56c7" xlink:to="loc_us-gaap_EquityComponentDomain_9fb7fc97-13d3-499c-8ac3-1e63947c56c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b2958fc8-a415-4d91-8903-e5926c802c2d" 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_9fb7fc97-13d3-499c-8ac3-1e63947c56c7" xlink:to="loc_us-gaap_EquityComponentDomain_b2958fc8-a415-4d91-8903-e5926c802c2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_8ca7aa13-abd8-4ed3-9c31-8a81fd7c50b4" 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_b2958fc8-a415-4d91-8903-e5926c802c2d" xlink:to="loc_us-gaap_CommonStockMember_8ca7aa13-abd8-4ed3-9c31-8a81fd7c50b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_144222c1-b053-4857-9196-807d2e986968" 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_b2958fc8-a415-4d91-8903-e5926c802c2d" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_144222c1-b053-4857-9196-807d2e986968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_70cfbaa0-eb42-4365-afd4-494a36a28166" 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_b2958fc8-a415-4d91-8903-e5926c802c2d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_70cfbaa0-eb42-4365-afd4-494a36a28166" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_b9d03b22-17da-4112-af80-aac1a3afed9a" 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_b2958fc8-a415-4d91-8903-e5926c802c2d" xlink:to="loc_us-gaap_RetainedEarningsMember_b9d03b22-17da-4112-af80-aac1a3afed9a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/STATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="sttk-20211231.xsd#STATEMENTSOFCASHFLOWS"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/STATEMENTSOFCASHFLOWS" xlink:type="extended" id="i13409c26af47412e8d7585c7fd6ae395_STATEMENTSOFCASHFLOWS">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" 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_NetCashProvidedByUsedInOperatingActivitiesAbstract_33fb35ce-8629-494a-ad96-73f5548ec294" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_33fb35ce-8629-494a-ad96-73f5548ec294" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_395ce1a1-b28b-45cc-ba70-f6ded3183776" 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_NetCashProvidedByUsedInOperatingActivitiesAbstract_33fb35ce-8629-494a-ad96-73f5548ec294" xlink:to="loc_us-gaap_NetIncomeLoss_395ce1a1-b28b-45cc-ba70-f6ded3183776" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_33fb35ce-8629-494a-ad96-73f5548ec294" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_5612d245-3b8a-49a8-a1e1-19d89e308cce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:to="loc_us-gaap_ShareBasedCompensation_5612d245-3b8a-49a8-a1e1-19d89e308cce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_65be597f-dc39-4aa0-a680-3d89c4682cc9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:to="loc_us-gaap_Depreciation_65be597f-dc39-4aa0-a680-3d89c4682cc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_afd8602e-739e-4809-8485-fe5a2991cdb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:to="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_afd8602e-739e-4809-8485-fe5a2991cdb2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_5c61c744-3c61-4b5d-9ba8-bc6e073fadff" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_2baaa5f9-601d-4cb0-8d12-9491868e16a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_2baaa5f9-601d-4cb0-8d12-9491868e16a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_9759e51a-b4ad-42cd-87ab-134b6a8dd4b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_9759e51a-b4ad-42cd-87ab-134b6a8dd4b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_06ac39ac-96e2-47fb-85de-c822c421c752" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_06ac39ac-96e2-47fb-85de-c822c421c752" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_346cc38f-1d1a-40de-b337-36f7050cb268" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_346cc38f-1d1a-40de-b337-36f7050cb268" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_fdf0391b-6060-452b-81fd-80d39aaeaf40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_fdf0391b-6060-452b-81fd-80d39aaeaf40" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_IncreaseDecreaseInDeferredRentCredits_3f68a1de-6439-4357-bc46-03e3314b1d9d" xlink:href="sttk-20211231.xsd#sttk_IncreaseDecreaseInDeferredRentCredits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_sttk_IncreaseDecreaseInDeferredRentCredits_3f68a1de-6439-4357-bc46-03e3314b1d9d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3e860031-d6c4-4de7-b708-4506b59cfa77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_c74df0b2-28ff-488d-847c-217d7b94ed6f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3e860031-d6c4-4de7-b708-4506b59cfa77" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_439afa9d-62ab-4344-a8be-adc8e4807a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_439afa9d-62ab-4344-a8be-adc8e4807a1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_2c3c5619-6f20-497c-9982-c83059db8970" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_2c3c5619-6f20-497c-9982-c83059db8970" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_12bdd92f-7844-4cd5-afcd-ee7972a3aa32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_12bdd92f-7844-4cd5-afcd-ee7972a3aa32" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2df654f4-e5f5-4304-8b96-0728aa6b2457" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_28db9624-2103-4799-a038-526ea1688e96" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2df654f4-e5f5-4304-8b96-0728aa6b2457" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_0715d2cc-7d4a-4f7e-8830-bc0745557244" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_0715d2cc-7d4a-4f7e-8830-bc0745557244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_de1f4d72-4d30-4bc9-be81-7a8dfb571f48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:to="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering_de1f4d72-4d30-4bc9-be81-7a8dfb571f48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_692b1e58-a124-419c-bebc-e2249c267295" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_692b1e58-a124-419c-bebc-e2249c267295" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepurchaseOfRedeemablePreferredStock_50ec696f-6f57-4c5b-9078-9c7e00119885" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromRepurchaseOfRedeemablePreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:to="loc_us-gaap_ProceedsFromRepurchaseOfRedeemablePreferredStock_50ec696f-6f57-4c5b-9078-9c7e00119885" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_cc6f17f6-edb1-42c1-8ac6-013a08a990d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5cd5b924-5993-4ce2-8358-caba00bf3c3f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_cc6f17f6-edb1-42c1-8ac6-013a08a990d7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_b0f9852a-b35d-4a73-a6a8-60219c858f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_b0f9852a-b35d-4a73-a6a8-60219c858f4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_b4cb6eda-3fa2-49e6-aab6-e7aff2b414f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_b4cb6eda-3fa2-49e6-aab6-e7aff2b414f9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_f0a08a65-7fb4-4cbf-8e42-942fddd5b949" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_83be20c3-936d-42c4-8272-482d5e733b6b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_83be20c3-936d-42c4-8272-482d5e733b6b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_67e3b997-4e6b-471a-8e08-567492211fad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_83be20c3-936d-42c4-8272-482d5e733b6b" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_67e3b997-4e6b-471a-8e08-567492211fad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_0a82e599-f91e-4751-be23-8fd306e6dc3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_83be20c3-936d-42c4-8272-482d5e733b6b" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_0a82e599-f91e-4751-be23-8fd306e6dc3d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_d74d665b-755b-4238-8d29-31d87ea6f4c2" 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_ef608ba2-d03b-4f98-a061-fc03efdd44b7" xlink:to="loc_us-gaap_StatementTable_d74d665b-755b-4238-8d29-31d87ea6f4c2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_43fbd3f0-32a5-416c-adff-08f5a45fb1ca" 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_StatementTable_d74d665b-755b-4238-8d29-31d87ea6f4c2" xlink:to="loc_us-gaap_StatementClassOfStockAxis_43fbd3f0-32a5-416c-adff-08f5a45fb1ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_43fbd3f0-32a5-416c-adff-08f5a45fb1ca_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_43fbd3f0-32a5-416c-adff-08f5a45fb1ca" xlink:to="loc_us-gaap_ClassOfStockDomain_43fbd3f0-32a5-416c-adff-08f5a45fb1ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_35a90188-9999-4d49-8140-0947fd7b258d" 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_43fbd3f0-32a5-416c-adff-08f5a45fb1ca" xlink:to="loc_us-gaap_ClassOfStockDomain_35a90188-9999-4d49-8140-0947fd7b258d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_SeriesB1PreferredStockMember_fe3e3372-12ea-4554-8ff4-731db58d3f71" xlink:href="sttk-20211231.xsd#sttk_SeriesB1PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_35a90188-9999-4d49-8140-0947fd7b258d" xlink:to="loc_sttk_SeriesB1PreferredStockMember_fe3e3372-12ea-4554-8ff4-731db58d3f71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_cce82373-daf2-4041-b662-96eb64e357d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_35a90188-9999-4d49-8140-0947fd7b258d" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_cce82373-daf2-4041-b662-96eb64e357d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_f9f87337-b387-40f3-ae46-23447c783c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d74d665b-755b-4238-8d29-31d87ea6f4c2" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_f9f87337-b387-40f3-ae46-23447c783c0b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_f9f87337-b387-40f3-ae46-23447c783c0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_f9f87337-b387-40f3-ae46-23447c783c0b" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_f9f87337-b387-40f3-ae46-23447c783c0b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c7725b8f-3e7c-4d2a-9c07-f3eae326b42c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_f9f87337-b387-40f3-ae46-23447c783c0b" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c7725b8f-3e7c-4d2a-9c07-f3eae326b42c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IPOMember_c986117f-860f-4963-8ed5-2b3a8b869095" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IPOMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_c7725b8f-3e7c-4d2a-9c07-f3eae326b42c" xlink:to="loc_us-gaap_IPOMember_c986117f-860f-4963-8ed5-2b3a8b869095" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#BasisofPresentationandSummaryofSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" id="ieccfdbdf3f3e400da2c7536a2381bbac_BasisofPresentationandSummaryofSignificantAccountingPoliciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_30cc5120-36bf-4cf9-817f-0b88dbd8a5cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4bd6d950-21bb-42a5-bca7-d5e2a5443cd3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_30cc5120-36bf-4cf9-817f-0b88dbd8a5cf" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4bd6d950-21bb-42a5-bca7-d5e2a5443cd3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6ebb9285-cdad-4863-91b6-1285d42300ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_30cc5120-36bf-4cf9-817f-0b88dbd8a5cf" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6ebb9285-cdad-4863-91b6-1285d42300ef" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_06a8871a-a5b1-46ee-85b3-5f556dc9ac70" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_6ebb9285-cdad-4863-91b6-1285d42300ef" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_06a8871a-a5b1-46ee-85b3-5f556dc9ac70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_06a8871a-a5b1-46ee-85b3-5f556dc9ac70_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_06a8871a-a5b1-46ee-85b3-5f556dc9ac70" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_06a8871a-a5b1-46ee-85b3-5f556dc9ac70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_05c33dec-cc3e-4029-8bd4-f6c420e20f7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_06a8871a-a5b1-46ee-85b3-5f556dc9ac70" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_05c33dec-cc3e-4029-8bd4-f6c420e20f7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_OperatingAccountMember_b287d59c-389c-413c-8cfc-15acc49995b1" xlink:href="sttk-20211231.xsd#sttk_OperatingAccountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_05c33dec-cc3e-4029-8bd4-f6c420e20f7a" xlink:to="loc_sttk_OperatingAccountMember_b287d59c-389c-413c-8cfc-15acc49995b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_26028a96-0836-4849-851e-196e006df0c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_05c33dec-cc3e-4029-8bd4-f6c420e20f7a" xlink:to="loc_us-gaap_MoneyMarketFundsMember_26028a96-0836-4849-851e-196e006df0c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_05f83803-c085-4285-8391-a87c17acbb26" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_05c33dec-cc3e-4029-8bd4-f6c420e20f7a" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_05f83803-c085-4285-8391-a87c17acbb26" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofpropertyandequipmentdepreciationandamortizationperiodsDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofpropertyandequipmentdepreciationandamortizationperiodsDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofpropertyandequipmentdepreciationandamortizationperiodsDetails" xlink:type="extended" id="i14ae19fa3c2842fe8694cd70ab1ebe42_BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofpropertyandequipmentdepreciationandamortizationperiodsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9abe69-5e52-428b-8841-8d9b3ee79964" 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_PropertyPlantAndEquipmentUsefulLife_302711a2-6525-402c-826c-28bde762529c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9abe69-5e52-428b-8841-8d9b3ee79964" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_302711a2-6525-402c-826c-28bde762529c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_d471c243-ab1a-4da2-804b-a52b29bd698f" 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_dd9abe69-5e52-428b-8841-8d9b3ee79964" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_d471c243-ab1a-4da2-804b-a52b29bd698f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a9011670-7b2f-49d0-b073-34f361bec1e9" 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_d471c243-ab1a-4da2-804b-a52b29bd698f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_a9011670-7b2f-49d0-b073-34f361bec1e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a9011670-7b2f-49d0-b073-34f361bec1e9_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_a9011670-7b2f-49d0-b073-34f361bec1e9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a9011670-7b2f-49d0-b073-34f361bec1e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" 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_a9011670-7b2f-49d0-b073-34f361bec1e9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OfficeEquipmentMember_cdcb9a29-0993-476d-ae88-f8b16d370db7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OfficeEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" xlink:to="loc_us-gaap_OfficeEquipmentMember_cdcb9a29-0993-476d-ae88-f8b16d370db7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_948ac67a-67f6-4d46-b52f-c8b09377c26d" 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_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_948ac67a-67f6-4d46-b52f-c8b09377c26d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_LabEquipmentMember_f09da99f-28da-45f9-96b5-52b3dedb4694" xlink:href="sttk-20211231.xsd#sttk_LabEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" xlink:to="loc_sttk_LabEquipmentMember_f09da99f-28da-45f9-96b5-52b3dedb4694" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_749c4176-2778-4c10-b140-115630a16639" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c51abb4b-4aa0-43d7-8bcc-c1d30635abe6" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_749c4176-2778-4c10-b140-115630a16639" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_82dfda42-fb1b-4bd6-81ec-2c0d7180293d" 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_ScheduleOfPropertyPlantAndEquipmentTable_d471c243-ab1a-4da2-804b-a52b29bd698f" xlink:to="loc_srt_RangeAxis_82dfda42-fb1b-4bd6-81ec-2c0d7180293d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_82dfda42-fb1b-4bd6-81ec-2c0d7180293d_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_82dfda42-fb1b-4bd6-81ec-2c0d7180293d" xlink:to="loc_srt_RangeMember_82dfda42-fb1b-4bd6-81ec-2c0d7180293d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a9a97642-7377-439b-85aa-5a5743663dfa" 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_82dfda42-fb1b-4bd6-81ec-2c0d7180293d" xlink:to="loc_srt_RangeMember_a9a97642-7377-439b-85aa-5a5743663dfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_e4169460-56c2-4a32-b593-9b648090b5e0" 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_a9a97642-7377-439b-85aa-5a5743663dfa" xlink:to="loc_srt_MinimumMember_e4169460-56c2-4a32-b593-9b648090b5e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d45cd078-5cbe-4a05-a300-6e31e90967e4" 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_a9a97642-7377-439b-85aa-5a5743663dfa" xlink:to="loc_srt_MaximumMember_d45cd078-5cbe-4a05-a300-6e31e90967e4" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofantidilutivesecuritiesDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofantidilutivesecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofantidilutivesecuritiesDetails" xlink:type="extended" id="i8cbdb087ee6c4e35bee26f7a4287f6bf_BasisofPresentationandSummaryofSignificantAccountingPoliciesScheduleofantidilutivesecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_38359475-1008-43ef-ba83-5a7da6c2432e" 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_c3209dfa-f2e8-4589-bc67-5efeaeef39bb" 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_38359475-1008-43ef-ba83-5a7da6c2432e" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_c3209dfa-f2e8-4589-bc67-5efeaeef39bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_f77ac847-55a3-41ff-a5b2-9a5559dff37b" 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_38359475-1008-43ef-ba83-5a7da6c2432e" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_f77ac847-55a3-41ff-a5b2-9a5559dff37b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_0b58f3c8-5c14-4822-b887-f1b8beab2ee2" 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_f77ac847-55a3-41ff-a5b2-9a5559dff37b" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_0b58f3c8-5c14-4822-b887-f1b8beab2ee2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_0b58f3c8-5c14-4822-b887-f1b8beab2ee2_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_0b58f3c8-5c14-4822-b887-f1b8beab2ee2" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_0b58f3c8-5c14-4822-b887-f1b8beab2ee2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9ed3837d-2a92-4147-8dec-21137305a9ad" 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_0b58f3c8-5c14-4822-b887-f1b8beab2ee2" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9ed3837d-2a92-4147-8dec-21137305a9ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_28b5ed64-6083-498f-8bcc-ec5dcc67379e" 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_9ed3837d-2a92-4147-8dec-21137305a9ad" xlink:to="loc_us-gaap_EmployeeStockOptionMember_28b5ed64-6083-498f-8bcc-ec5dcc67379e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_e68b6397-4331-4ba3-a7a6-ff937efad9fe" 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_AntidilutiveSecuritiesNameDomain_9ed3837d-2a92-4147-8dec-21137305a9ad" xlink:to="loc_us-gaap_RestrictedStockMember_e68b6397-4331-4ba3-a7a6-ff937efad9fe" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/ShortTermInvestmentsScheduleofavailableforsaleshortterminvestmentsDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#ShortTermInvestmentsScheduleofavailableforsaleshortterminvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/ShortTermInvestmentsScheduleofavailableforsaleshortterminvestmentsDetails" xlink:type="extended" id="i937f582deebd4d18a911ef8e2be8a661_ShortTermInvestmentsScheduleofavailableforsaleshortterminvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd75fb9b-2fc8-4e4d-ad17-86263301ece5" 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_DebtSecuritiesAbstract_88769bee-a856-4f3d-a5f0-18ba85e4bb4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd75fb9b-2fc8-4e4d-ad17-86263301ece5" xlink:to="loc_us-gaap_DebtSecuritiesAbstract_88769bee-a856-4f3d-a5f0-18ba85e4bb4a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_e6678474-8766-4614-bbe1-9a7f2df048e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_88769bee-a856-4f3d-a5f0-18ba85e4bb4a" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_e6678474-8766-4614-bbe1-9a7f2df048e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax_436007d8-98ad-4b9e-941f-3b5eccd37685" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_88769bee-a856-4f3d-a5f0-18ba85e4bb4a" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax_436007d8-98ad-4b9e-941f-3b5eccd37685" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_65c0217f-139e-41eb-b004-66dba3426f96" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_88769bee-a856-4f3d-a5f0-18ba85e4bb4a" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_65c0217f-139e-41eb-b004-66dba3426f96" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_6ad14cf9-dc51-431d-9b99-8ce72c3a9657" 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_fd75fb9b-2fc8-4e4d-ad17-86263301ece5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_6ad14cf9-dc51-431d-9b99-8ce72c3a9657" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb" 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_6ad14cf9-dc51-431d-9b99-8ce72c3a9657" xlink:to="loc_us-gaap_FinancialInstrumentAxis_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb_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_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0b941a6e-4877-4aa0-924f-4d9d57d1620b" 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_37e7b01d-dc8b-4eb6-a238-b09cfa936ffb" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0b941a6e-4877-4aa0-924f-4d9d57d1620b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_48a44069-3899-461f-8fe9-602ad0283afb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USTreasuryAndGovernmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0b941a6e-4877-4aa0-924f-4d9d57d1620b" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_48a44069-3899-461f-8fe9-602ad0283afb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/PropertyandEquipmentScheduleofpropertyandequipmentDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#PropertyandEquipmentScheduleofpropertyandequipmentDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/PropertyandEquipmentScheduleofpropertyandequipmentDetails" xlink:type="extended" id="i0bb740a083454bb4bf6d78d180ebcf1b_PropertyandEquipmentScheduleofpropertyandequipmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55affa18-041b-415e-b600-58d4caf4916c" 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_PropertyPlantAndEquipmentGross_f2e00e61-1ea1-4d84-83fd-4cb57a02e687" 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_55affa18-041b-415e-b600-58d4caf4916c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_f2e00e61-1ea1-4d84-83fd-4cb57a02e687" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_a08b89b7-eefa-431f-bedc-a4de8b738395" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55affa18-041b-415e-b600-58d4caf4916c" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_a08b89b7-eefa-431f-bedc-a4de8b738395" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_faa87d70-e475-4ae9-b85b-d2ce9efddd56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55affa18-041b-415e-b600-58d4caf4916c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_faa87d70-e475-4ae9-b85b-d2ce9efddd56" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_a091c10a-3920-4254-b550-f74425dd1950" 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_55affa18-041b-415e-b600-58d4caf4916c" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_a091c10a-3920-4254-b550-f74425dd1950" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_253f2af6-674a-4c52-81f8-dafac4f01899" 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_a091c10a-3920-4254-b550-f74425dd1950" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_253f2af6-674a-4c52-81f8-dafac4f01899" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_253f2af6-674a-4c52-81f8-dafac4f01899_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_253f2af6-674a-4c52-81f8-dafac4f01899" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_253f2af6-674a-4c52-81f8-dafac4f01899_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" 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_253f2af6-674a-4c52-81f8-dafac4f01899" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_LabEquipmentMember_c720ce9f-5fad-46ba-8bad-ee790572e941" xlink:href="sttk-20211231.xsd#sttk_LabEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:to="loc_sttk_LabEquipmentMember_c720ce9f-5fad-46ba-8bad-ee790572e941" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_c52f10c2-45f9-4680-8d44-94d37d3dbae5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_c52f10c2-45f9-4680-8d44-94d37d3dbae5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_819d3390-ec12-4bc1-8b43-1d0b39f2b55c" 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_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:to="loc_us-gaap_ConstructionInProgressMember_819d3390-ec12-4bc1-8b43-1d0b39f2b55c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_d7b8dce9-0e1d-4495-8bb9-a43c55d30be9" 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_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_d7b8dce9-0e1d-4495-8bb9-a43c55d30be9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OfficeEquipmentMember_6b329631-3f84-4d01-afd9-c4c6759e13c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OfficeEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cf397d12-417d-4ba2-8d55-98b2ee5cc63b" xlink:to="loc_us-gaap_OfficeEquipmentMember_6b329631-3f84-4d01-afd9-c4c6759e13c7" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/PreferredStockDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#PreferredStockDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/PreferredStockDetails" xlink:type="extended" id="i77674fd023814cc3abc98575f2c94bea_PreferredStockDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLineItems_14fe25d6-66be-4a58-b2a8-1754d1a50646" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_2ee46246-faa4-4611-ac57-6d98173287e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_14fe25d6-66be-4a58-b2a8-1754d1a50646" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_2ee46246-faa4-4611-ac57-6d98173287e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_2fa7b7bc-b105-4a92-b915-4466a2c67c08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_14fe25d6-66be-4a58-b2a8-1754d1a50646" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_2fa7b7bc-b105-4a92-b915-4466a2c67c08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_3fb6c3af-e934-4c03-b03a-a2e962f8f5a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_14fe25d6-66be-4a58-b2a8-1754d1a50646" xlink:to="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_3fb6c3af-e934-4c03-b03a-a2e962f8f5a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityByClassOfStockTable_d7888ec4-a3f2-4ed7-957a-21cd2d5436e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TemporaryEquityByClassOfStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TemporaryEquityLineItems_14fe25d6-66be-4a58-b2a8-1754d1a50646" xlink:to="loc_us-gaap_TemporaryEquityByClassOfStockTable_d7888ec4-a3f2-4ed7-957a-21cd2d5436e9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_6c734d14-c4a2-48e8-8bc9-6f58baef495e" 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_TemporaryEquityByClassOfStockTable_d7888ec4-a3f2-4ed7-957a-21cd2d5436e9" xlink:to="loc_us-gaap_StatementClassOfStockAxis_6c734d14-c4a2-48e8-8bc9-6f58baef495e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_6c734d14-c4a2-48e8-8bc9-6f58baef495e_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_6c734d14-c4a2-48e8-8bc9-6f58baef495e" xlink:to="loc_us-gaap_ClassOfStockDomain_6c734d14-c4a2-48e8-8bc9-6f58baef495e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_62d81aa6-6615-4f3d-b1f4-d5b1b0549f7d" 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_6c734d14-c4a2-48e8-8bc9-6f58baef495e" xlink:to="loc_us-gaap_ClassOfStockDomain_62d81aa6-6615-4f3d-b1f4-d5b1b0549f7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableConvertiblePreferredStockMember_16cb1a82-8718-4878-9e59-83ce9cd42759" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_62d81aa6-6615-4f3d-b1f4-d5b1b0549f7d" xlink:to="loc_us-gaap_RedeemableConvertiblePreferredStockMember_16cb1a82-8718-4878-9e59-83ce9cd42759" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_98932372-809d-485a-aadd-74c4e2117d02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RedeemableConvertiblePreferredStockMember_16cb1a82-8718-4878-9e59-83ce9cd42759" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_98932372-809d-485a-aadd-74c4e2117d02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_SeriesB1PreferredStockMember_9c67135a-728a-4006-a8cc-9b2bf9a21d89" xlink:href="sttk-20211231.xsd#sttk_SeriesB1PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RedeemableConvertiblePreferredStockMember_16cb1a82-8718-4878-9e59-83ce9cd42759" xlink:to="loc_sttk_SeriesB1PreferredStockMember_9c67135a-728a-4006-a8cc-9b2bf9a21d89" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/CollaborationAgreementRelatedPartyDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#CollaborationAgreementRelatedPartyDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/CollaborationAgreementRelatedPartyDetails" xlink:type="extended" id="i746ef66d5ebd46419aaeeaafe223c013_CollaborationAgreementRelatedPartyDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_1a159838-f559-495b-9571-ea19196f61bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromCollaborators_53271698-a659-41ee-a572-a2e8705f7a46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromCollaborators"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1a159838-f559-495b-9571-ea19196f61bb" xlink:to="loc_us-gaap_ProceedsFromCollaborators_53271698-a659-41ee-a572-a2e8705f7a46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_45a663e2-24d4-4384-a9c8-87c36c3b6c7a" 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_RelatedPartyTransactionLineItems_1a159838-f559-495b-9571-ea19196f61bb" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_45a663e2-24d4-4384-a9c8-87c36c3b6c7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_b0c2921d-a0a2-4320-9035-c122fc01a8a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1a159838-f559-495b-9571-ea19196f61bb" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_b0c2921d-a0a2-4320-9035-c122fc01a8a2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_6d37cc23-accb-438e-adfe-bdb96fb506a3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_b0c2921d-a0a2-4320-9035-c122fc01a8a2" xlink:to="loc_srt_CounterpartyNameAxis_6d37cc23-accb-438e-adfe-bdb96fb506a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6d37cc23-accb-438e-adfe-bdb96fb506a3_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_6d37cc23-accb-438e-adfe-bdb96fb506a3" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6d37cc23-accb-438e-adfe-bdb96fb506a3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e2d9b0bb-ad7b-4fa0-af1b-665619f1af13" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_6d37cc23-accb-438e-adfe-bdb96fb506a3" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e2d9b0bb-ad7b-4fa0-af1b-665619f1af13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_TakedaMember_57ab3a0a-6747-4291-9c74-04e91f899850" xlink:href="sttk-20211231.xsd#sttk_TakedaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e2d9b0bb-ad7b-4fa0-af1b-665619f1af13" xlink:to="loc_sttk_TakedaMember_57ab3a0a-6747-4291-9c74-04e91f899850" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_b0c2921d-a0a2-4320-9035-c122fc01a8a2" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683" xlink:to="loc_us-gaap_RelatedPartyDomain_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_29a1dec3-2ed9-497b-8ad3-3820e3609cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cd32dafb-f9ca-4eb0-b67a-5c6f27cec683" xlink:to="loc_us-gaap_RelatedPartyDomain_29a1dec3-2ed9-497b-8ad3-3820e3609cb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestorMember_e1e49224-592b-49c6-a4d5-9768a944c4d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_29a1dec3-2ed9-497b-8ad3-3820e3609cb8" xlink:to="loc_us-gaap_InvestorMember_e1e49224-592b-49c6-a4d5-9768a944c4d9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_b06cae69-6c29-47e5-b772-bf3293ac015d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_b0c2921d-a0a2-4320-9035-c122fc01a8a2" xlink:to="loc_us-gaap_TypeOfArrangementAxis_b06cae69-6c29-47e5-b772-bf3293ac015d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_b06cae69-6c29-47e5-b772-bf3293ac015d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_b06cae69-6c29-47e5-b772-bf3293ac015d" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_b06cae69-6c29-47e5-b772-bf3293ac015d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f3489ff2-472f-45bf-810e-c68bf7994527" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_b06cae69-6c29-47e5-b772-bf3293ac015d" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f3489ff2-472f-45bf-810e-c68bf7994527" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementMember_c4259a4a-aff7-4ae4-b558-ea4a099547a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollaborativeArrangementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f3489ff2-472f-45bf-810e-c68bf7994527" xlink:to="loc_us-gaap_CollaborativeArrangementMember_c4259a4a-aff7-4ae4-b558-ea4a099547a7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/StockBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#StockBasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended" id="i426c53a79b524de6b995b20e409c820e_StockBasedCompensationNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" 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_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesAuthorizedAnnualIncreasePercentage_3fe4496c-dae8-41a5-bdd2-6017917dce51" xlink:href="sttk-20211231.xsd#sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesAuthorizedAnnualIncreasePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesAuthorizedAnnualIncreasePercentage_3fe4496c-dae8-41a5-bdd2-6017917dce51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_b5581cbc-eabf-466c-9d06-3227c3a1eef4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_b5581cbc-eabf-466c-9d06-3227c3a1eef4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_CommonStockAdditionalCapitalSharesReservedForFutureIssuance_9fc0f52e-91cc-40a4-8244-4410ea55e548" xlink:href="sttk-20211231.xsd#sttk_CommonStockAdditionalCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_sttk_CommonStockAdditionalCapitalSharesReservedForFutureIssuance_9fc0f52e-91cc-40a4-8244-4410ea55e548" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3f861c5f-d0a5-4307-ab15-5eaedc42fc82" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3f861c5f-d0a5-4307-ab15-5eaedc42fc82" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_833100cd-fe8e-4cae-8e07-479b81b38d90" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_833100cd-fe8e-4cae-8e07-479b81b38d90" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_e462d755-498a-40f7-9392-5f0bbe2d6b98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_e462d755-498a-40f7-9392-5f0bbe2d6b98" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_3e63ba00-7319-4e6c-873d-616ac71370c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_3e63ba00-7319-4e6c-873d-616ac71370c4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumSharesPerEmployeeValue_3dd6bfec-0436-4a9b-b49f-c946c13abd1b" xlink:href="sttk-20211231.xsd#sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumSharesPerEmployeeValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumSharesPerEmployeeValue_3dd6bfec-0436-4a9b-b49f-c946c13abd1b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee_49a08b27-aaa3-4ccc-ae17-df19a4f08064" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee_49a08b27-aaa3-4ccc-ae17-df19a4f08064" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualIncreaseInNumberOfSharesAuthorizedTerm_7378b2f5-1fb6-4d46-bd99-f21944578bc6" xlink:href="sttk-20211231.xsd#sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualIncreaseInNumberOfSharesAuthorizedTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_sttk_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualIncreaseInNumberOfSharesAuthorizedTerm_7378b2f5-1fb6-4d46-bd99-f21944578bc6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d613edac-62c3-46c9-a4c5-1f108c268917" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d613edac-62c3-46c9-a4c5-1f108c268917" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockPlans_cabdfa5b-3805-41d7-9902-315720a1d0c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromStockPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ProceedsFromStockPlans_cabdfa5b-3805-41d7-9902-315720a1d0c2" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f1b94670-470a-4986-9369-ef615d53727d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f1b94670-470a-4986-9369-ef615d53727d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_6f8f2c39-9275-44d7-a1b0-df3e1d0de048" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_6f8f2c39-9275-44d7-a1b0-df3e1d0de048" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_63eb346a-3876-41d7-ae7c-c4e3ae098ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_63eb346a-3876-41d7-ae7c-c4e3ae098ebc" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_6a40475a-7ac5-408f-97f2-f69630d9cf65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_6a40475a-7ac5-408f-97f2-f69630d9cf65" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_10159f25-5198-4c28-9b26-264ca37cbcd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_10159f25-5198-4c28-9b26-264ca37cbcd0" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_5fba0fda-3665-414c-8d5b-fe83578f76c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_5fba0fda-3665-414c-8d5b-fe83578f76c9" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_980f0b7b-cfb4-4e14-ac81-d7299ee740f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_980f0b7b-cfb4-4e14-ac81-d7299ee740f0" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_30f39af7-4805-4319-813b-9db37cf0c974" 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_c629d40a-9c33-49ca-b5b8-dca87f1c7f72" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_30f39af7-4805-4319-813b-9db37cf0c974" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_f4756875-479b-4d82-80ce-fe127c8ba6d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_30f39af7-4805-4319-813b-9db37cf0c974" xlink:to="loc_us-gaap_PlanNameAxis_f4756875-479b-4d82-80ce-fe127c8ba6d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f4756875-479b-4d82-80ce-fe127c8ba6d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_f4756875-479b-4d82-80ce-fe127c8ba6d3" xlink:to="loc_us-gaap_PlanNameDomain_f4756875-479b-4d82-80ce-fe127c8ba6d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_33e1443b-4360-423a-bd77-6877c01e047a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_f4756875-479b-4d82-80ce-fe127c8ba6d3" xlink:to="loc_us-gaap_PlanNameDomain_33e1443b-4360-423a-bd77-6877c01e047a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_A2020StockIncentivePlanMember_a903f244-587a-4138-99c1-fe4f2b803f51" xlink:href="sttk-20211231.xsd#sttk_A2020StockIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_33e1443b-4360-423a-bd77-6877c01e047a" xlink:to="loc_sttk_A2020StockIncentivePlanMember_a903f244-587a-4138-99c1-fe4f2b803f51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_A2020EmployeeStockPurchasePlanMember_e215e395-ddbd-4d84-b2e4-62cf1c4815ca" xlink:href="sttk-20211231.xsd#sttk_A2020EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_33e1443b-4360-423a-bd77-6877c01e047a" xlink:to="loc_sttk_A2020EmployeeStockPurchasePlanMember_e215e395-ddbd-4d84-b2e4-62cf1c4815ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a3342f31-c814-4e25-9e4e-cc3a91a4aa47" 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_30f39af7-4805-4319-813b-9db37cf0c974" xlink:to="loc_us-gaap_AwardTypeAxis_a3342f31-c814-4e25-9e4e-cc3a91a4aa47" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a3342f31-c814-4e25-9e4e-cc3a91a4aa47_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_a3342f31-c814-4e25-9e4e-cc3a91a4aa47" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a3342f31-c814-4e25-9e4e-cc3a91a4aa47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1915d27f-54e2-4d02-af8b-3e092974f0f6" 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_a3342f31-c814-4e25-9e4e-cc3a91a4aa47" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1915d27f-54e2-4d02-af8b-3e092974f0f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_fa97dd09-13c7-4f70-af70-f7fe4339a920" 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_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1915d27f-54e2-4d02-af8b-3e092974f0f6" xlink:to="loc_us-gaap_EmployeeStockOptionMember_fa97dd09-13c7-4f70-af70-f7fe4339a920" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_3a27e861-fae2-4458-a735-6eabcca6acd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_30f39af7-4805-4319-813b-9db37cf0c974" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_3a27e861-fae2-4458-a735-6eabcca6acd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3a27e861-fae2-4458-a735-6eabcca6acd5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3a27e861-fae2-4458-a735-6eabcca6acd5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3a27e861-fae2-4458-a735-6eabcca6acd5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_6e409b04-cde3-4cd3-9a1b-7f97927f58e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3a27e861-fae2-4458-a735-6eabcca6acd5" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_6e409b04-cde3-4cd3-9a1b-7f97927f58e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_8931fb16-2859-4758-89b5-a7667f7440e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_6e409b04-cde3-4cd3-9a1b-7f97927f58e0" xlink:to="loc_us-gaap_SubsequentEventMember_8931fb16-2859-4758-89b5-a7667f7440e9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/StockBasedCompensationScheduleofstockbasedcompensationexpenseDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#StockBasedCompensationScheduleofstockbasedcompensationexpenseDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/StockBasedCompensationScheduleofstockbasedcompensationexpenseDetails" xlink:type="extended" id="i1a1417d9913745918431765644f531b0_StockBasedCompensationScheduleofstockbasedcompensationexpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14a110cd-c971-42b1-a6dd-144b1a639ffb" 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_AllocatedShareBasedCompensationExpense_6f11b538-a851-4cb9-bc5c-215befa4adeb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14a110cd-c971-42b1-a6dd-144b1a639ffb" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_6f11b538-a851-4cb9-bc5c-215befa4adeb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e71eb281-fa23-4468-a7e5-fcb9396d4821" 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_14a110cd-c971-42b1-a6dd-144b1a639ffb" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e71eb281-fa23-4468-a7e5-fcb9396d4821" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_51ac6dbb-4691-453b-b95a-fa7689cc5e94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e71eb281-fa23-4468-a7e5-fcb9396d4821" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_51ac6dbb-4691-453b-b95a-fa7689cc5e94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_51ac6dbb-4691-453b-b95a-fa7689cc5e94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_51ac6dbb-4691-453b-b95a-fa7689cc5e94" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_51ac6dbb-4691-453b-b95a-fa7689cc5e94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6d832093-535c-4671-bdf6-a0e97b42a6f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_51ac6dbb-4691-453b-b95a-fa7689cc5e94" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6d832093-535c-4671-bdf6-a0e97b42a6f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_3fcaeaa0-5fad-4317-b15e-0af337607b25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_6d832093-535c-4671-bdf6-a0e97b42a6f3" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_3fcaeaa0-5fad-4317-b15e-0af337607b25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_06636ecb-87cd-4b29-bac1-6b794104277a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_6d832093-535c-4671-bdf6-a0e97b42a6f3" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_06636ecb-87cd-4b29-bac1-6b794104277a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/StockBasedCompensationScheduleof2020PlanvaluationassumptionsDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#StockBasedCompensationScheduleof2020PlanvaluationassumptionsDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/StockBasedCompensationScheduleof2020PlanvaluationassumptionsDetails" xlink:type="extended" id="i2c1812ff3929466a9448d676973bd945_StockBasedCompensationScheduleof2020PlanvaluationassumptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" 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_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_0a04db77-d86d-43ce-928a-617dcd41ead2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_0a04db77-d86d-43ce-928a-617dcd41ead2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_53202eb3-8935-42e5-8e85-e9710b6b6878" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_53202eb3-8935-42e5-8e85-e9710b6b6878" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_d64200bb-3974-4781-8b86-eaacc92fb991" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_d64200bb-3974-4781-8b86-eaacc92fb991" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_dd681eb4-2a95-48ad-8d78-4c358f551599" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_dd681eb4-2a95-48ad-8d78-4c358f551599" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1f37d050-3f5b-405c-980a-ca4df311fef7" 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_f670dbc2-4665-44bc-bb04-6f63e5ff1df8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1f37d050-3f5b-405c-980a-ca4df311fef7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c" 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_1f37d050-3f5b-405c-980a-ca4df311fef7" xlink:to="loc_us-gaap_AwardTypeAxis_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c_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_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ae109c33-8e42-41f1-b9a6-659c6d7c4509" 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_cc09858a-388d-4e5e-9aa7-c9cdbd8ca45c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ae109c33-8e42-41f1-b9a6-659c6d7c4509" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_0118be4f-bef7-483d-8fc5-be0f7cc15cf7" 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_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ae109c33-8e42-41f1-b9a6-659c6d7c4509" xlink:to="loc_us-gaap_EmployeeStockOptionMember_0118be4f-bef7-483d-8fc5-be0f7cc15cf7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_419c7010-00b9-4307-8f3d-57a4dd156aeb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1f37d050-3f5b-405c-980a-ca4df311fef7" xlink:to="loc_us-gaap_PlanNameAxis_419c7010-00b9-4307-8f3d-57a4dd156aeb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_419c7010-00b9-4307-8f3d-57a4dd156aeb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_419c7010-00b9-4307-8f3d-57a4dd156aeb" xlink:to="loc_us-gaap_PlanNameDomain_419c7010-00b9-4307-8f3d-57a4dd156aeb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_c6cc9948-3e36-4b4a-8b7f-252abd3fe953" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_419c7010-00b9-4307-8f3d-57a4dd156aeb" xlink:to="loc_us-gaap_PlanNameDomain_c6cc9948-3e36-4b4a-8b7f-252abd3fe953" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_A2020StockIncentivePlanMember_51a48d8f-e816-497f-be8a-ad2230cf7247" xlink:href="sttk-20211231.xsd#sttk_A2020StockIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_c6cc9948-3e36-4b4a-8b7f-252abd3fe953" xlink:to="loc_sttk_A2020StockIncentivePlanMember_51a48d8f-e816-497f-be8a-ad2230cf7247" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/StockBasedCompensationScheduleof2020ESPPvaluationassumptionsDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#StockBasedCompensationScheduleof2020ESPPvaluationassumptionsDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/StockBasedCompensationScheduleof2020ESPPvaluationassumptionsDetails" xlink:type="extended" id="iaee1539c5a8644ff93a75c2a0148af4f_StockBasedCompensationScheduleof2020ESPPvaluationassumptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0131b2b8-98c2-428c-82b0-64ed093c73c9" 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_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_5442d332-7dcb-4e81-bfb8-97365e8dd549" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0131b2b8-98c2-428c-82b0-64ed093c73c9" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_5442d332-7dcb-4e81-bfb8-97365e8dd549" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_89e9f471-2e60-4b14-be0a-e46ae216c972" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0131b2b8-98c2-428c-82b0-64ed093c73c9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_89e9f471-2e60-4b14-be0a-e46ae216c972" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_bbccfbc7-a80c-4fa8-9deb-af76d0a7829c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0131b2b8-98c2-428c-82b0-64ed093c73c9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_bbccfbc7-a80c-4fa8-9deb-af76d0a7829c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_71f98c72-8987-4773-8ff8-4bc52da1f4e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0131b2b8-98c2-428c-82b0-64ed093c73c9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_71f98c72-8987-4773-8ff8-4bc52da1f4e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0055c608-c568-42d9-b063-809b880486d5" 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_0131b2b8-98c2-428c-82b0-64ed093c73c9" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0055c608-c568-42d9-b063-809b880486d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_529d8718-666b-4a4c-9296-2b9bea0154e2" 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_0055c608-c568-42d9-b063-809b880486d5" xlink:to="loc_us-gaap_AwardTypeAxis_529d8718-666b-4a4c-9296-2b9bea0154e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_529d8718-666b-4a4c-9296-2b9bea0154e2_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_529d8718-666b-4a4c-9296-2b9bea0154e2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_529d8718-666b-4a4c-9296-2b9bea0154e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1131190-4d4b-44bf-9f63-5ccea2eaab95" 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_529d8718-666b-4a4c-9296-2b9bea0154e2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1131190-4d4b-44bf-9f63-5ccea2eaab95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_fd36b3be-e61e-44b4-8235-09e8932e4188" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1131190-4d4b-44bf-9f63-5ccea2eaab95" xlink:to="loc_us-gaap_EmployeeStockMember_fd36b3be-e61e-44b4-8235-09e8932e4188" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_c8310652-6420-4aa3-bb73-c3ca05853706" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0055c608-c568-42d9-b063-809b880486d5" xlink:to="loc_us-gaap_PlanNameAxis_c8310652-6420-4aa3-bb73-c3ca05853706" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_c8310652-6420-4aa3-bb73-c3ca05853706_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_c8310652-6420-4aa3-bb73-c3ca05853706" xlink:to="loc_us-gaap_PlanNameDomain_c8310652-6420-4aa3-bb73-c3ca05853706_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_a8eeaf02-bdfb-4573-8c31-c1a2f0ac8d89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_c8310652-6420-4aa3-bb73-c3ca05853706" xlink:to="loc_us-gaap_PlanNameDomain_a8eeaf02-bdfb-4573-8c31-c1a2f0ac8d89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_A2020EmployeeStockPurchasePlanMember_40d4b98a-628e-4294-9c54-eb9aa2538faa" xlink:href="sttk-20211231.xsd#sttk_A2020EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_a8eeaf02-bdfb-4573-8c31-c1a2f0ac8d89" xlink:to="loc_sttk_A2020EmployeeStockPurchasePlanMember_40d4b98a-628e-4294-9c54-eb9aa2538faa" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/StockBasedCompensationScheduleofrestrictedstockactivityDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#StockBasedCompensationScheduleofrestrictedstockactivityDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/StockBasedCompensationScheduleofrestrictedstockactivityDetails" xlink:type="extended" id="icb538af027164ae7be428fbeb0131284_StockBasedCompensationScheduleofrestrictedstockactivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9fadf5ac-2990-4fec-bcd6-2d2a1a8e4ab1" 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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4ffb99-d9d9-4184-9e9a-292fdc1a0ae3" 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_9fadf5ac-2990-4fec-bcd6-2d2a1a8e4ab1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4ffb99-d9d9-4184-9e9a-292fdc1a0ae3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_985ffb4f-361f-4957-8bd0-afac9f7a63bf" 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_6a4ffb99-d9d9-4184-9e9a-292fdc1a0ae3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_985ffb4f-361f-4957-8bd0-afac9f7a63bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a30282f5-9a71-4e5a-b5cf-f8069f1fd072" 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_6a4ffb99-d9d9-4184-9e9a-292fdc1a0ae3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a30282f5-9a71-4e5a-b5cf-f8069f1fd072" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_93c68ad3-da7c-4398-97ed-b72865592b43" 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_0d434d3d-e635-400e-a7f0-089feb15f3f7" 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_9fadf5ac-2990-4fec-bcd6-2d2a1a8e4ab1" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0d434d3d-e635-400e-a7f0-089feb15f3f7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a" 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_0d434d3d-e635-400e-a7f0-089feb15f3f7" xlink:to="loc_us-gaap_AwardTypeAxis_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a_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_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ddc2b72b-bccb-42d5-80a5-8edead1a9653" 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_24d0d9e2-3f22-4cee-8b77-cb76f0adfc5a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ddc2b72b-bccb-42d5-80a5-8edead1a9653" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_eae79850-5199-428e-8f35-7c66423e6f18" 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_ddc2b72b-bccb-42d5-80a5-8edead1a9653" xlink:to="loc_us-gaap_RestrictedStockMember_eae79850-5199-428e-8f35-7c66423e6f18" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#IncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended" id="ie89cddd8c9e945b4a8c90f0291678827_IncomeTaxesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_1c20f741-e22e-4e25-ab3b-6f482fd289bb" 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_ValuationAllowanceDeferredTaxAssetChangeInAmount_8fc53f19-e337-4d9e-9def-d5796e80a447" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_1c20f741-e22e-4e25-ab3b-6f482fd289bb" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_8fc53f19-e337-4d9e-9def-d5796e80a447" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_0fd4c7e6-973b-4d4c-b766-ffd765f645aa" 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_1c20f741-e22e-4e25-ab3b-6f482fd289bb" xlink:to="loc_us-gaap_OperatingLossCarryforwards_0fd4c7e6-973b-4d4c-b766-ffd765f645aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_ba170761-7619-484e-a5fc-aff89e90483c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_1c20f741-e22e-4e25-ab3b-6f482fd289bb" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_ba170761-7619-484e-a5fc-aff89e90483c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_a2220f99-5fcf-4879-80eb-01974a0c7fee" 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_1c20f741-e22e-4e25-ab3b-6f482fd289bb" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_a2220f99-5fcf-4879-80eb-01974a0c7fee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_0cad989f-b60d-4957-8f57-de0af7b309e5" 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_a2220f99-5fcf-4879-80eb-01974a0c7fee" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_0cad989f-b60d-4957-8f57-de0af7b309e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_0cad989f-b60d-4957-8f57-de0af7b309e5_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_0cad989f-b60d-4957-8f57-de0af7b309e5" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_0cad989f-b60d-4957-8f57-de0af7b309e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_b1b91474-f5ea-47ae-a389-ba4f0791bcfd" 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_0cad989f-b60d-4957-8f57-de0af7b309e5" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_b1b91474-f5ea-47ae-a389-ba4f0791bcfd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_e6b96a82-113c-4d3e-a591-0c9aa286a2f0" 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_b1b91474-f5ea-47ae-a389-ba4f0791bcfd" xlink:to="loc_us-gaap_DomesticCountryMember_e6b96a82-113c-4d3e-a591-0c9aa286a2f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_c585c8c3-974a-450b-a895-572c07c6a0d0" 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_b1b91474-f5ea-47ae-a389-ba4f0791bcfd" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_c585c8c3-974a-450b-a895-572c07c6a0d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAxis_adfc3f59-1b87-4105-bbac-39397b4bacaa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCreditCarryforwardAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_a2220f99-5fcf-4879-80eb-01974a0c7fee" xlink:to="loc_us-gaap_TaxCreditCarryforwardAxis_adfc3f59-1b87-4105-bbac-39397b4bacaa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardNameDomain_adfc3f59-1b87-4105-bbac-39397b4bacaa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxCreditCarryforwardAxis_adfc3f59-1b87-4105-bbac-39397b4bacaa" xlink:to="loc_us-gaap_TaxCreditCarryforwardNameDomain_adfc3f59-1b87-4105-bbac-39397b4bacaa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardNameDomain_f143bc18-b8ec-4b1e-b813-f91bbc975505" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxCreditCarryforwardAxis_adfc3f59-1b87-4105-bbac-39397b4bacaa" xlink:to="loc_us-gaap_TaxCreditCarryforwardNameDomain_f143bc18-b8ec-4b1e-b813-f91bbc975505" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalLossCarryforwardMember_1c50ff45-e24e-4bd0-b356-ec70103325fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalLossCarryforwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardNameDomain_f143bc18-b8ec-4b1e-b813-f91bbc975505" xlink:to="loc_us-gaap_CapitalLossCarryforwardMember_1c50ff45-e24e-4bd0-b356-ec70103325fd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.shattucklabs.com/role/RelatedPartyDetails" xlink:type="simple" xlink:href="sttk-20211231.xsd#RelatedPartyDetails"/>
  <link:definitionLink xlink:role="http://www.shattucklabs.com/role/RelatedPartyDetails" xlink:type="extended" id="i55ed1a9ec25b4238b825fe71500654c0_RelatedPartyDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_9da2ee84-1a42-48a3-a932-9a3565837539" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_ShareholderOwnershipPercentage_f1a8eced-1f6c-481e-8a22-c18eaf75f780" xlink:href="sttk-20211231.xsd#sttk_ShareholderOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9da2ee84-1a42-48a3-a932-9a3565837539" xlink:to="loc_sttk_ShareholderOwnershipPercentage_f1a8eced-1f6c-481e-8a22-c18eaf75f780" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7a11f4d7-5969-4733-a2b4-b54eebc6a78c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9da2ee84-1a42-48a3-a932-9a3565837539" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7a11f4d7-5969-4733-a2b4-b54eebc6a78c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_58d5fc39-2879-410b-b75f-bc29818f333d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7a11f4d7-5969-4733-a2b4-b54eebc6a78c" xlink:to="loc_dei_LegalEntityAxis_58d5fc39-2879-410b-b75f-bc29818f333d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_58d5fc39-2879-410b-b75f-bc29818f333d_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_58d5fc39-2879-410b-b75f-bc29818f333d" xlink:to="loc_dei_EntityDomain_58d5fc39-2879-410b-b75f-bc29818f333d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_7965dd4b-8795-4690-9a00-f1a0559732de" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_58d5fc39-2879-410b-b75f-bc29818f333d" xlink:to="loc_dei_EntityDomain_7965dd4b-8795-4690-9a00-f1a0559732de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sttk_TakedaMember_c2672f90-60f6-44e4-bec1-1daa463e0668" xlink:href="sttk-20211231.xsd#sttk_TakedaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7965dd4b-8795-4690-9a00-f1a0559732de" xlink:to="loc_sttk_TakedaMember_c2672f90-60f6-44e4-bec1-1daa463e0668" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
