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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2023 Workiva-->
<!--r:51117aaf-da85-496c-8de0-90d410b847ed,g:a23aa42e-7fd5-43b9-a154-6a3866900e75-->
<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://enphase.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="enph-20230930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://enphase.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_480e7aab-0c79-435c-86b5-4ae891d2f067" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_480e7aab-0c79-435c-86b5-4ae891d2f067" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_8e073840-ebcf-4dfe-8701-db4af8cadec7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_StockholdersEquity_8e073840-ebcf-4dfe-8701-db4af8cadec7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_4a722137-52a7-454f-bcdd-cc0fa0c2d651" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_4a722137-52a7-454f-bcdd-cc0fa0c2d651" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ff999afe-8033-4cee-bd34-4488eb7c912c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ff999afe-8033-4cee-bd34-4488eb7c912c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_cd6ae0e3-2246-46bc-a5cd-bda034b0898d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_cd6ae0e3-2246-46bc-a5cd-bda034b0898d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature_8b986fc0-6c4f-476a-87fa-9adbedc51da0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtWithConversionFeature_8b986fc0-6c4f-476a-87fa-9adbedc51da0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d795446d-1c21-40c7-8583-da072b908750" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d795446d-1c21-40c7-8583-da072b908750" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_acef7e0b-d373-41a1-bb64-329460e19a04" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_acef7e0b-d373-41a1-bb64-329460e19a04" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_bf862095-c014-4778-a53f-93286252f74b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockRetiredCostMethodAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_bf862095-c014-4778-a53f-93286252f74b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_acf17bae-8475-46eb-a672-9b0d6b50bb08" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_acf17bae-8475-46eb-a672-9b0d6b50bb08" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_c924c06c-907a-4d85-a135-de11fa719bfb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_NetIncomeLoss_c924c06c-907a-4d85-a135-de11fa719bfb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_30e1dde3-69dc-4869-aa5a-195888757463" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_30e1dde3-69dc-4869-aa5a-195888757463" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_4b77d60f-3774-4151-ada8-b9d039c8de4f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_4b77d60f-3774-4151-ada8-b9d039c8de4f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_2fc0b116-850c-4e8f-9b09-0ce0f52e549d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdateExtensibleList_bbf31536-2d7d-47b8-80bc-cb714291601f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdateExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5992f5a8-2ee4-4daa-8e3f-ecd8ce4c09f5" xlink:to="loc_us-gaap_AccountingStandardsUpdateExtensibleList_bbf31536-2d7d-47b8-80bc-cb714291601f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_2cf01750-5a38-4e24-ae66-1b2355c09562" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_480e7aab-0c79-435c-86b5-4ae891d2f067" xlink:to="loc_us-gaap_StatementTable_2cf01750-5a38-4e24-ae66-1b2355c09562" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2cf01750-5a38-4e24-ae66-1b2355c09562" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947" xlink:to="loc_us-gaap_EquityComponentDomain_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3bfc3b77-f810-4ce2-9f9c-3a4ebe83a947" xlink:to="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_4738901f-944d-4970-9c0e-d9f8f7dc3e50" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:to="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_4738901f-944d-4970-9c0e-d9f8f7dc3e50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_cb76551e-8167-4251-9bf8-762825cb492a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:to="loc_us-gaap_RetainedEarningsMember_cb76551e-8167-4251-9bf8-762825cb492a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dae8760d-b0f0-41d7-bad3-6c35833cc385" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dae8760d-b0f0-41d7-bad3-6c35833cc385" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_595329c0-d76c-4615-ac90-434a76229666" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_dafba623-a0c5-4c09-bc19-0c6d38da72fa" xlink:to="loc_us-gaap_TreasuryStockCommonMember_595329c0-d76c-4615-ac90-434a76229666" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2cf01750-5a38-4e24-ae66-1b2355c09562" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2dcb619e-afd0-4c33-8a63-4002160ccec4" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_6e0a59bf-0eba-4c49-bb43-5550dd7fa77e" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2dcb619e-afd0-4c33-8a63-4002160ccec4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_cd7ba196-b804-4683-b9bb-b84ebe72eaee" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2dcb619e-afd0-4c33-8a63-4002160ccec4" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_cd7ba196-b804-4683-b9bb-b84ebe72eaee" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/REVENUERECOGNITIONSummaryofDisaggregatedRevenuebyPrimaryGeographicalMarketandTimingofRevenueRecognitionDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#REVENUERECOGNITIONSummaryofDisaggregatedRevenuebyPrimaryGeographicalMarketandTimingofRevenueRecognitionDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/REVENUERECOGNITIONSummaryofDisaggregatedRevenuebyPrimaryGeographicalMarketandTimingofRevenueRecognitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_ad5c189e-513d-4b83-844b-6549c47fb1fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8410b976-ec13-4e53-aa92-9071fbdbfe07" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_ad5c189e-513d-4b83-844b-6549c47fb1fa" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8410b976-ec13-4e53-aa92-9071fbdbfe07" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_c908ab8f-c179-47b1-a2fd-f06de2401686" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_ad5c189e-513d-4b83-844b-6549c47fb1fa" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_c908ab8f-c179-47b1-a2fd-f06de2401686" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_f4d67ba8-69af-4252-a911-f126ecb9ca4a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c908ab8f-c179-47b1-a2fd-f06de2401686" xlink:to="loc_srt_StatementGeographicalAxis_f4d67ba8-69af-4252-a911-f126ecb9ca4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f4d67ba8-69af-4252-a911-f126ecb9ca4a_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_f4d67ba8-69af-4252-a911-f126ecb9ca4a" xlink:to="loc_srt_SegmentGeographicalDomain_f4d67ba8-69af-4252-a911-f126ecb9ca4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_9212beeb-9104-4140-8d6b-95129573d6ae" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_f4d67ba8-69af-4252-a911-f126ecb9ca4a" xlink:to="loc_srt_SegmentGeographicalDomain_9212beeb-9104-4140-8d6b-95129573d6ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_f082088e-525e-495d-82d9-47542585a3ca" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_9212beeb-9104-4140-8d6b-95129573d6ae" xlink:to="loc_country_US_f082088e-525e-495d-82d9-47542585a3ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_InternationalMember_8366914d-e930-41c1-b387-6bda715813d5" xlink:href="enph-20230930.xsd#enph_InternationalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_9212beeb-9104-4140-8d6b-95129573d6ae" xlink:to="loc_enph_InternationalMember_8366914d-e930-41c1-b387-6bda715813d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_7fc2554c-672a-41a1-825b-294a2dda50af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c908ab8f-c179-47b1-a2fd-f06de2401686" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_7fc2554c-672a-41a1-825b-294a2dda50af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_7fc2554c-672a-41a1-825b-294a2dda50af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_7fc2554c-672a-41a1-825b-294a2dda50af" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_7fc2554c-672a-41a1-825b-294a2dda50af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3f39ccfb-692c-4d77-9be6-87115e9c1dbe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_7fc2554c-672a-41a1-825b-294a2dda50af" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3f39ccfb-692c-4d77-9be6-87115e9c1dbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_6053c1d3-d767-489a-87e1-72e6acd334ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3f39ccfb-692c-4d77-9be6-87115e9c1dbe" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_6053c1d3-d767-489a-87e1-72e6acd334ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_c13221af-0458-47e7-8833-11a678d2fb86" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3f39ccfb-692c-4d77-9be6-87115e9c1dbe" xlink:to="loc_us-gaap_TransferredOverTimeMember_c13221af-0458-47e7-8833-11a678d2fb86" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_970c2ca0-8d1a-43fe-8708-8f76eee96089" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_970c2ca0-8d1a-43fe-8708-8f76eee96089" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_19eaa4e4-12d5-4d0f-b2d0-645d032ae4fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_19eaa4e4-12d5-4d0f-b2d0-645d032ae4fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_63440db9-64a6-4057-abe2-a0bb752934bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_63440db9-64a6-4057-abe2-a0bb752934bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_051c6e3c-5eec-48c1-9fb3-f11fafe2b884" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_63440db9-64a6-4057-abe2-a0bb752934bd" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_051c6e3c-5eec-48c1-9fb3-f11fafe2b884" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails_1" xlink:type="simple" xlink:href="enph-20230930.xsd#REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails_1"/>
  <link:definitionLink xlink:role="http://enphase.com/role/REVENUERECOGNITIONSummaryofEstimatedRevenueExpectedtobeRecognizedinFuturePeriodsDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_970c2ca0-8d1a-43fe-8708-8f76eee96089" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_970c2ca0-8d1a-43fe-8708-8f76eee96089" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_19eaa4e4-12d5-4d0f-b2d0-645d032ae4fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_19eaa4e4-12d5-4d0f-b2d0-645d032ae4fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_63440db9-64a6-4057-abe2-a0bb752934bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_159dbdea-dbda-44ae-b85b-ccb18ede1b55" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_63440db9-64a6-4057-abe2-a0bb752934bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSScheduleofAcquiredIntangibleAssetsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#GOODWILLANDINTANGIBLEASSETSScheduleofAcquiredIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSScheduleofAcquiredIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0f407454-3f5a-454d-a41d-bda098731336" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_e0f40d0d-fb41-4ab8-9cfc-9cc178ac6f75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0f407454-3f5a-454d-a41d-bda098731336" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_e0f40d0d-fb41-4ab8-9cfc-9cc178ac6f75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_e0f40d0d-fb41-4ab8-9cfc-9cc178ac6f75" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_dcc58675-78ee-4d87-b3d7-0efbd526b2a4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_dcc58675-78ee-4d87-b3d7-0efbd526b2a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_ca09caa7-34fc-4e29-8ed3-86024be552f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_ca09caa7-34fc-4e29-8ed3-86024be552f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_b085dc5f-b09f-4543-aa8a-b7dc959fcef4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_b085dc5f-b09f-4543-aa8a-b7dc959fcef4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_a16892cc-fc26-4a94-8107-59cdfe514a2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_a16892cc-fc26-4a94-8107-59cdfe514a2d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_d1930a08-5c5f-4955-b2df-67508b1de956" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_d1930a08-5c5f-4955-b2df-67508b1de956" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_467363ef-fd8c-4f02-83ca-338f7c91562c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_2a1486e0-91cd-496f-a68f-0ab84ad1529a" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_467363ef-fd8c-4f02-83ca-338f7c91562c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_c478437e-02e5-4086-94b9-7cb0f52a8ea5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0f407454-3f5a-454d-a41d-bda098731336" xlink:to="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_c478437e-02e5-4086-94b9-7cb0f52a8ea5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ae8c853b-7225-41aa-9300-adb7a638e3e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_c478437e-02e5-4086-94b9-7cb0f52a8ea5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ae8c853b-7225-41aa-9300-adb7a638e3e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ae8c853b-7225-41aa-9300-adb7a638e3e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ae8c853b-7225-41aa-9300-adb7a638e3e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ae8c853b-7225-41aa-9300-adb7a638e3e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ae8c853b-7225-41aa-9300-adb7a638e3e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntellectualPropertyMember_6cba6cf5-3817-4848-86f8-8463ca88133f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntellectualPropertyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:to="loc_us-gaap_IntellectualPropertyMember_6cba6cf5-3817-4848-86f8-8463ca88133f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_2ce64335-7651-4c63-8108-894b49afc3e4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:to="loc_us-gaap_CustomerRelationshipsMember_2ce64335-7651-4c63-8108-894b49afc3e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_f6f0df97-67e7-4c5a-a5b9-600857d86c74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:to="loc_us-gaap_TradeNamesMember_f6f0df97-67e7-4c5a-a5b9-600857d86c74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_7d509bdf-a6a3-42d0-9269-0faacae6b75c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OrderOrProductionBacklogMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5625e6f8-aa5c-4697-a88f-94673e3057ec" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_7d509bdf-a6a3-42d0-9269-0faacae6b75c" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSNarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#GOODWILLANDINTANGIBLEASSETSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e2d538d5-60e3-4325-a3d0-5cc83e7721d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss_d05bf352-74e0-431a-a834-128189c02d39" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e2d538d5-60e3-4325-a3d0-5cc83e7721d7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss_d05bf352-74e0-431a-a834-128189c02d39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_49b716c4-9408-4714-adfa-967dffafbca7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e2d538d5-60e3-4325-a3d0-5cc83e7721d7" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_49b716c4-9408-4714-adfa-967dffafbca7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0a90342d-920d-41e7-8eb4-c15ec06728f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_49b716c4-9408-4714-adfa-967dffafbca7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0a90342d-920d-41e7-8eb4-c15ec06728f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0a90342d-920d-41e7-8eb4-c15ec06728f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0a90342d-920d-41e7-8eb4-c15ec06728f5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0a90342d-920d-41e7-8eb4-c15ec06728f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_bb4695cf-1c80-455a-b8d3-d36c4df4973b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0a90342d-920d-41e7-8eb4-c15ec06728f5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_bb4695cf-1c80-455a-b8d3-d36c4df4973b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0b8b3e20-a51b-4ad9-a552-c670cf68d10d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_49b716c4-9408-4714-adfa-967dffafbca7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0b8b3e20-a51b-4ad9-a552-c670cf68d10d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0b8b3e20-a51b-4ad9-a552-c670cf68d10d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0b8b3e20-a51b-4ad9-a552-c670cf68d10d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0b8b3e20-a51b-4ad9-a552-c670cf68d10d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f233bd85-3896-4b22-9597-810d4364e09e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0b8b3e20-a51b-4ad9-a552-c670cf68d10d" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f233bd85-3896-4b22-9597-810d4364e09e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_GreenComNetworksAGMember_04931cf5-4566-45b9-ada6-a297f8e6336c" xlink:href="enph-20230930.xsd#enph_GreenComNetworksAGMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f233bd85-3896-4b22-9597-810d4364e09e" xlink:to="loc_enph_GreenComNetworksAGMember_04931cf5-4566-45b9-ada6-a297f8e6336c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSAmortizationExpenseDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#GOODWILLANDINTANGIBLEASSETSAmortizationExpenseDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/GOODWILLANDINTANGIBLEASSETSAmortizationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_28910d4b-9568-4124-8cde-5b223ef758cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_07ff9c25-ae90-4a0c-a2c5-68ac639862b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_28910d4b-9568-4124-8cde-5b223ef758cf" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_07ff9c25-ae90-4a0c-a2c5-68ac639862b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_46276e07-311b-4483-8ed5-2d2c54ec2a08" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_28910d4b-9568-4124-8cde-5b223ef758cf" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_46276e07-311b-4483-8ed5-2d2c54ec2a08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_46276e07-311b-4483-8ed5-2d2c54ec2a08" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_42fa9208-d6ab-4d26-8c90-4b57aa93d9ba" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_e28aefa2-94f7-4af2-9052-b16a1d0ca2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_e28aefa2-94f7-4af2-9052-b16a1d0ca2cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_071846d2-fe74-4f53-956c-fb2812f31c31" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:to="loc_us-gaap_CustomerRelationshipsMember_071846d2-fe74-4f53-956c-fb2812f31c31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_8a18f506-16eb-4433-aaab-141b9cf180aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:to="loc_us-gaap_TradeNamesMember_8a18f506-16eb-4433-aaab-141b9cf180aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_8449d053-c059-4916-8228-cc0c4793473d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OrderOrProductionBacklogMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ea8395df-969b-4114-bcc0-02830dbeea91" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_8449d053-c059-4916-8228-cc0c4793473d" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/CASHEQUIVALENTSANDMARKETABLESECURITIESScheduleofInvestmentsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#CASHEQUIVALENTSANDMARKETABLESECURITIESScheduleofInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/CASHEQUIVALENTSANDMARKETABLESECURITIESScheduleofInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_eed21970-8d4b-483c-9e1c-14d75edd3fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_eed21970-8d4b-483c-9e1c-14d75edd3fb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_11829920-ba0b-413f-aaf0-f3793f75e2ab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_11829920-ba0b-413f-aaf0-f3793f75e2ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_4d5a2853-e7a4-48f2-8227-acb711a6379f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_4d5a2853-e7a4-48f2-8227-acb711a6379f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_aa1f3c91-33fd-4667-a077-a0799358de89" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_aa1f3c91-33fd-4667-a077-a0799358de89" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28740b35-ae24-4535-8561-e1400ff67acd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_d0da1899-5e19-402a-b665-b6fe3b7391f1" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28740b35-ae24-4535-8561-e1400ff67acd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28740b35-ae24-4535-8561-e1400ff67acd" xlink:to="loc_us-gaap_FinancialInstrumentAxis_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_003ee0b4-09ef-4273-a6db-a0dbc6a1cc4f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_32d316c1-072b-40bb-a25b-13f7defb52cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_us-gaap_MoneyMarketFundsMember_32d316c1-072b-40bb-a25b-13f7defb52cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CertificatesOfDepositMember_fe6438f6-466c-4ff8-b78b-c3d531ec9fce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CertificatesOfDepositMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_us-gaap_CertificatesOfDepositMember_fe6438f6-466c-4ff8-b78b-c3d531ec9fce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_b5c7b9ec-1dd1-4cc2-8167-6491a9a1a1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_us-gaap_CommercialPaperMember_b5c7b9ec-1dd1-4cc2-8167-6491a9a1a1d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_c565abf9-387e-47b0-a5f9-021fce7a62a6" xlink:href="enph-20230930.xsd#enph_CorporateBondSecuritiesAndNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_c565abf9-387e-47b0-a5f9-021fce7a62a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_86e5f656-5129-444f-8f73-ea037e040f38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_86e5f656-5129-444f-8f73-ea037e040f38" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_eadc7bfe-ac2d-4c0d-b337-6a300714a1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_80b7ec11-2ee7-4af9-a7e9-2ef0c6098ef1" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_eadc7bfe-ac2d-4c0d-b337-6a300714a1d2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_b8337277-1bc9-406d-8295-89598fbb7ce3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28740b35-ae24-4535-8561-e1400ff67acd" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_b8337277-1bc9-406d-8295-89598fbb7ce3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_b8337277-1bc9-406d-8295-89598fbb7ce3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_b8337277-1bc9-406d-8295-89598fbb7ce3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_b8337277-1bc9-406d-8295-89598fbb7ce3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_41839c1b-7c51-4a07-a9e1-dcf89a6a68bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_b8337277-1bc9-406d-8295-89598fbb7ce3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_41839c1b-7c51-4a07-a9e1-dcf89a6a68bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_e2a8d6e4-4e96-4629-8bc0-b0b4750fbfa9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_41839c1b-7c51-4a07-a9e1-dcf89a6a68bd" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_e2a8d6e4-4e96-4629-8bc0-b0b4750fbfa9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_MarketableSecuritiesMember_8b044947-b20a-425c-b8b0-96a4002e1dda" xlink:href="enph-20230930.xsd#enph_MarketableSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_41839c1b-7c51-4a07-a9e1-dcf89a6a68bd" xlink:to="loc_enph_MarketableSecuritiesMember_8b044947-b20a-425c-b8b0-96a4002e1dda" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/WARRANTYOBLIGATIONSNarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#WARRANTYOBLIGATIONSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/WARRANTYOBLIGATIONSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyLiabilityLineItems_473c4ce2-aad8-4aab-80ea-ae1770a211a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductWarrantyLiabilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease_9ee885b7-0820-49a9-8d8b-f3f73d778f26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_473c4ce2-aad8-4aab-80ea-ae1770a211a1" xlink:to="loc_us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease_9ee885b7-0820-49a9-8d8b-f3f73d778f26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ProductWarrantyTerm_3ddd87b5-0ea4-41ae-9acd-573a6ae11131" xlink:href="enph-20230930.xsd#enph_ProductWarrantyTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_473c4ce2-aad8-4aab-80ea-ae1770a211a1" xlink:to="loc_enph_ProductWarrantyTerm_3ddd87b5-0ea4-41ae-9acd-573a6ae11131" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyLiabilityTable_9412e3ba-48fc-4075-9189-1821d938d164" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductWarrantyLiabilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ProductWarrantyLiabilityLineItems_473c4ce2-aad8-4aab-80ea-ae1770a211a1" xlink:to="loc_us-gaap_ProductWarrantyLiabilityTable_9412e3ba-48fc-4075-9189-1821d938d164" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyVariableAxis_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c" xlink:href="enph-20230930.xsd#enph_WarrantyVariableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ProductWarrantyLiabilityTable_9412e3ba-48fc-4075-9189-1821d938d164" xlink:to="loc_enph_WarrantyVariableAxis_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyVariableDomain_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c_default" xlink:href="enph-20230930.xsd#enph_WarrantyVariableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_enph_WarrantyVariableAxis_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c" xlink:to="loc_enph_WarrantyVariableDomain_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:href="enph-20230930.xsd#enph_WarrantyVariableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_enph_WarrantyVariableAxis_7cf6f366-2be2-4a93-ad2d-5e96f90efc5c" xlink:to="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ProductReplacementCostsRelatedToEnphaseIQBatterySystemsMember_341c17cd-ad16-49a8-9543-604b8182e677" xlink:href="enph-20230930.xsd#enph_ProductReplacementCostsRelatedToEnphaseIQBatterySystemsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_ProductReplacementCostsRelatedToEnphaseIQBatterySystemsMember_341c17cd-ad16-49a8-9543-604b8182e677" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_FieldPerformanceDataAndDiagnosticRootCauseFailureAnalysisMember_4e94e3d7-7826-4aec-bb0b-47ab435bf244" xlink:href="enph-20230930.xsd#enph_FieldPerformanceDataAndDiagnosticRootCauseFailureAnalysisMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_FieldPerformanceDataAndDiagnosticRootCauseFailureAnalysisMember_4e94e3d7-7826-4aec-bb0b-47ab435bf244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PriorGenerationProductsMember_bb852346-f712-4051-b63a-d4a106f0400d" xlink:href="enph-20230930.xsd#enph_PriorGenerationProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_PriorGenerationProductsMember_bb852346-f712-4051-b63a-d4a106f0400d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ProductReplacementCostsRelatedToOtherProductsMember_4adba966-d02a-4cc1-ae6b-9430ec5af79a" xlink:href="enph-20230930.xsd#enph_ProductReplacementCostsRelatedToOtherProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_ProductReplacementCostsRelatedToOtherProductsMember_4adba966-d02a-4cc1-ae6b-9430ec5af79a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ChangeInWarrantyPeriodMember_5ba32e5e-4221-49cd-ab38-23dda3672a41" xlink:href="enph-20230930.xsd#enph_ChangeInWarrantyPeriodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_ChangeInWarrantyPeriodMember_5ba32e5e-4221-49cd-ab38-23dda3672a41" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ExpeditedFreightCostsAndReplacementCostsMember_d4856c71-0806-4d64-ae40-08a94446fa82" xlink:href="enph-20230930.xsd#enph_ExpeditedFreightCostsAndReplacementCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_ExpeditedFreightCostsAndReplacementCostsMember_d4856c71-0806-4d64-ae40-08a94446fa82" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_LaborReimbursementRateMember_2041a612-e700-4a4d-9049-aa04b5c9b698" xlink:href="enph-20230930.xsd#enph_LaborReimbursementRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyVariableDomain_46759b98-3627-4a96-ba8c-18f27ce21c0e" xlink:to="loc_enph_LaborReimbursementRateMember_2041a612-e700-4a4d-9049-aa04b5c9b698" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_765703b6-98cd-46e5-bfc0-ed670bd5c1f3" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ProductWarrantyLiabilityTable_9412e3ba-48fc-4075-9189-1821d938d164" xlink:to="loc_srt_RangeAxis_765703b6-98cd-46e5-bfc0-ed670bd5c1f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_765703b6-98cd-46e5-bfc0-ed670bd5c1f3_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_765703b6-98cd-46e5-bfc0-ed670bd5c1f3" xlink:to="loc_srt_RangeMember_765703b6-98cd-46e5-bfc0-ed670bd5c1f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6805d8fa-4039-4cbd-8d32-6d1dd6045cd9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_765703b6-98cd-46e5-bfc0-ed670bd5c1f3" xlink:to="loc_srt_RangeMember_6805d8fa-4039-4cbd-8d32-6d1dd6045cd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_b2c649ac-7ee6-437b-838e-de3fa2d2b4f7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6805d8fa-4039-4cbd-8d32-6d1dd6045cd9" xlink:to="loc_srt_MinimumMember_b2c649ac-7ee6-437b-838e-de3fa2d2b4f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_fe26930c-839b-4ad8-aefa-e73350e7de7e" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6805d8fa-4039-4cbd-8d32-6d1dd6045cd9" xlink:to="loc_srt_MaximumMember_fe26930c-839b-4ad8-aefa-e73350e7de7e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_ced77c86-5b3d-4398-9529-d88fbb2c2d11" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_ced77c86-5b3d-4398-9529-d88fbb2c2d11" xlink:to="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7665fc37-9ee1-439e-a2b0-c5266ee5dc6e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7665fc37-9ee1-439e-a2b0-c5266ee5dc6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_870957b5-e3ac-47b5-9e6f-a65a17c2e962" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_870957b5-e3ac-47b5-9e6f-a65a17c2e962" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecurities_33f6420c-d578-45f0-b31e-b592ffd16fd8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:to="loc_us-gaap_DebtSecurities_33f6420c-d578-45f0-b31e-b592ffd16fd8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_56eb73a5-3de0-48b6-996f-444e295f3198" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1baa221e-d376-4725-88be-84823637b601" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_56eb73a5-3de0-48b6-996f-444e295f3198" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_4b217189-88c2-4fca-aa5d-183f2244a6ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_ced77c86-5b3d-4398-9529-d88fbb2c2d11" xlink:to="loc_us-gaap_LiabilitiesAbstract_4b217189-88c2-4fca-aa5d-183f2244a6ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyObligationsAbstract_e278763d-a610-41ff-b3c2-99ce4625d01c" xlink:href="enph-20230930.xsd#enph_WarrantyObligationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_4b217189-88c2-4fca-aa5d-183f2244a6ce" xlink:to="loc_enph_WarrantyObligationsAbstract_e278763d-a610-41ff-b3c2-99ce4625d01c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_StandardAndExtendedProductWarrantyAccrualCurrentFairValueDisclosure_d8388df5-e109-46e7-8bff-33a6a7f47a23" xlink:href="enph-20230930.xsd#enph_StandardAndExtendedProductWarrantyAccrualCurrentFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyObligationsAbstract_e278763d-a610-41ff-b3c2-99ce4625d01c" xlink:to="loc_enph_StandardAndExtendedProductWarrantyAccrualCurrentFairValueDisclosure_d8388df5-e109-46e7-8bff-33a6a7f47a23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_StandardAndExtendedProductWarrantyAccrualNoncurrentFairValueDisclosure_0e6494f1-40ed-4543-b4f7-c6f0fca95fce" xlink:href="enph-20230930.xsd#enph_StandardAndExtendedProductWarrantyAccrualNoncurrentFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyObligationsAbstract_e278763d-a610-41ff-b3c2-99ce4625d01c" xlink:to="loc_enph_StandardAndExtendedProductWarrantyAccrualNoncurrentFairValueDisclosure_0e6494f1-40ed-4543-b4f7-c6f0fca95fce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_StandardAndExtendedProductWarrantyAccrualFairValueDisclosure_c29e2e12-43f6-4b99-abed-1972d3f4d7cd" xlink:href="enph-20230930.xsd#enph_StandardAndExtendedProductWarrantyAccrualFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WarrantyObligationsAbstract_e278763d-a610-41ff-b3c2-99ce4625d01c" xlink:to="loc_enph_StandardAndExtendedProductWarrantyAccrualFairValueDisclosure_c29e2e12-43f6-4b99-abed-1972d3f4d7cd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_a994575d-bec3-4c1d-a972-6c64318d7808" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_4b217189-88c2-4fca-aa5d-183f2244a6ce" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_a994575d-bec3-4c1d-a972-6c64318d7808" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_ced77c86-5b3d-4398-9529-d88fbb2c2d11" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006eb8a5-e875-40f9-8760-55358d2d4834" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006eb8a5-e875-40f9-8760-55358d2d4834" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_006eb8a5-e875-40f9-8760-55358d2d4834_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006eb8a5-e875-40f9-8760-55358d2d4834" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_006eb8a5-e875-40f9-8760-55358d2d4834_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_151b2789-0e02-4267-a8f4-cb367cbd9f02" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_006eb8a5-e875-40f9-8760-55358d2d4834" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_151b2789-0e02-4267-a8f4-cb367cbd9f02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_99f8412e-08be-4839-8cdb-335defb63734" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_151b2789-0e02-4267-a8f4-cb367cbd9f02" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_99f8412e-08be-4839-8cdb-335defb63734" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48f655eb-4d9b-4a5d-aa91-fefd1926a21f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48f655eb-4d9b-4a5d-aa91-fefd1926a21f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_48f655eb-4d9b-4a5d-aa91-fefd1926a21f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48f655eb-4d9b-4a5d-aa91-fefd1926a21f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_48f655eb-4d9b-4a5d-aa91-fefd1926a21f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9243c31c-f6b5-43fd-8cbf-34a6f6cfbd79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48f655eb-4d9b-4a5d-aa91-fefd1926a21f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9243c31c-f6b5-43fd-8cbf-34a6f6cfbd79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_0f9b0902-c2b0-4f85-bf0d-fbff05067b08" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9243c31c-f6b5-43fd-8cbf-34a6f6cfbd79" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_0f9b0902-c2b0-4f85-bf0d-fbff05067b08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_fe130e7b-5092-4a43-bcbe-745d000387e8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9243c31c-f6b5-43fd-8cbf-34a6f6cfbd79" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_fe130e7b-5092-4a43-bcbe-745d000387e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_61cdecac-c1e3-4e45-a9bc-57b224ebcfa9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9243c31c-f6b5-43fd-8cbf-34a6f6cfbd79" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_61cdecac-c1e3-4e45-a9bc-57b224ebcfa9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_6ed96383-4642-4852-8caa-ec72d586d111" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_6ed96383-4642-4852-8caa-ec72d586d111" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6ed96383-4642-4852-8caa-ec72d586d111_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_6ed96383-4642-4852-8caa-ec72d586d111" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6ed96383-4642-4852-8caa-ec72d586d111_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_6ed96383-4642-4852-8caa-ec72d586d111" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_c5dec9c4-26e8-449b-a26f-2a659f3cccc3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:to="loc_us-gaap_MoneyMarketFundsMember_c5dec9c4-26e8-449b-a26f-2a659f3cccc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_c9ef86ac-483c-4a1d-a13f-b2d73ab86a32" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:to="loc_us-gaap_CommercialPaperMember_c9ef86ac-483c-4a1d-a13f-b2d73ab86a32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_f4da5a9a-cc00-4261-b77a-84c20c57bccb" xlink:href="enph-20230930.xsd#enph_CorporateBondSecuritiesAndNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:to="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_f4da5a9a-cc00-4261-b77a-84c20c57bccb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_150cffd6-3feb-48e1-ac7f-da6c4c2129f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_50c4c5cc-d8d9-4fcc-8ff5-6c194b64ab58" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_150cffd6-3feb-48e1-ac7f-da6c4c2129f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_c87346f5-512e-4921-a2a5-b05cda8c0e8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_bde81ef7-28ec-4a59-86a9-f8ed348c3ca6" xlink:to="loc_us-gaap_FinancialInstrumentAxis_c87346f5-512e-4921-a2a5-b05cda8c0e8f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c87346f5-512e-4921-a2a5-b05cda8c0e8f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c87346f5-512e-4921-a2a5-b05cda8c0e8f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c87346f5-512e-4921-a2a5-b05cda8c0e8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c87346f5-512e-4921-a2a5-b05cda8c0e8f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CertificatesOfDepositMember_0660cb6f-b8a2-4863-9c79-8109d84b6fb9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CertificatesOfDepositMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:to="loc_us-gaap_CertificatesOfDepositMember_0660cb6f-b8a2-4863-9c79-8109d84b6fb9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_b131c743-ec54-4c92-bca6-fddfc2c4a139" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:to="loc_us-gaap_CommercialPaperMember_b131c743-ec54-4c92-bca6-fddfc2c4a139" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_91dcc785-1bab-4f1b-b8cb-4cc808ce21b9" xlink:href="enph-20230930.xsd#enph_CorporateBondSecuritiesAndNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:to="loc_enph_CorporateBondSecuritiesAndNoteSecuritiesMember_91dcc785-1bab-4f1b-b8cb-4cc808ce21b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_cd7919d8-89ce-4343-a3b8-9edc3dc2190b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_cd7919d8-89ce-4343-a3b8-9edc3dc2190b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_75ace449-8426-4872-9dad-99160a3d27c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ff25b322-451d-4c54-84fc-c46f1ed6f714" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_75ace449-8426-4872-9dad-99160a3d27c9" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#FAIRVALUEMEASUREMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_f385e1f5-942e-434f-a8bb-febdde5698c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_f385e1f5-942e-434f-a8bb-febdde5698c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecurities_1309675d-5dcb-4913-a086-19dbea59663a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_us-gaap_DebtSecurities_1309675d-5dcb-4913-a086-19dbea59663a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueLiabilityResultingFromOnePercentagePointIncreaseInProfitElementAndRiskPremium_83cc2826-d688-473f-9016-a35bfcb62db5" xlink:href="enph-20230930.xsd#enph_WarrantyObligationsAtFairValueIncreaseInFairValueLiabilityResultingFromOnePercentagePointIncreaseInProfitElementAndRiskPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueLiabilityResultingFromOnePercentagePointIncreaseInProfitElementAndRiskPremium_83cc2826-d688-473f-9016-a35bfcb62db5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyObligationsAtFairValueDecreaseInFairValueLiabilityResultingFromOnePercentagePointDecreaseInProfitElementAndRiskPremium_767facc5-1dfc-4422-a158-8feaefa52615" xlink:href="enph-20230930.xsd#enph_WarrantyObligationsAtFairValueDecreaseInFairValueLiabilityResultingFromOnePercentagePointDecreaseInProfitElementAndRiskPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_enph_WarrantyObligationsAtFairValueDecreaseInFairValueLiabilityResultingFromOnePercentagePointDecreaseInProfitElementAndRiskPremium_767facc5-1dfc-4422-a158-8feaefa52615" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyObligationsAtFairValueDecreaseInFairValueResultingFromOnePercentagePointIncreaseInDiscountRate_79d22820-b4f6-461d-a143-d215f81e6986" xlink:href="enph-20230930.xsd#enph_WarrantyObligationsAtFairValueDecreaseInFairValueResultingFromOnePercentagePointIncreaseInDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_enph_WarrantyObligationsAtFairValueDecreaseInFairValueResultingFromOnePercentagePointIncreaseInDiscountRate_79d22820-b4f6-461d-a143-d215f81e6986" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate_a583cfa6-26f4-4663-ba6d-32d3968f2b94" xlink:href="enph-20230930.xsd#enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_enph_WarrantyObligationsAtFairValueIncreaseInFairValueResultingFromOnePercentagePointDecreaseInDiscountRate_a583cfa6-26f4-4663-ba6d-32d3968f2b94" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8c6768a2-f5a0-42f2-b521-1cf3fb714c9a" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fd9cf525-aab2-4e5e-88c5-177bc336a791" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fd9cf525-aab2-4e5e-88c5-177bc336a791" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_fd9cf525-aab2-4e5e-88c5-177bc336a791_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fd9cf525-aab2-4e5e-88c5-177bc336a791" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_fd9cf525-aab2-4e5e-88c5-177bc336a791_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f3cd9412-d10a-46ca-93b1-931fe796b20c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fd9cf525-aab2-4e5e-88c5-177bc336a791" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f3cd9412-d10a-46ca-93b1-931fe796b20c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_92229a50-9a68-40f2-8196-afbf9db2619c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f3cd9412-d10a-46ca-93b1-931fe796b20c" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_92229a50-9a68-40f2-8196-afbf9db2619c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_fa0195e7-b67c-4a30-b2da-32a8657557f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_fa0195e7-b67c-4a30-b2da-32a8657557f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_fa0195e7-b67c-4a30-b2da-32a8657557f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_fa0195e7-b67c-4a30-b2da-32a8657557f2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_fa0195e7-b67c-4a30-b2da-32a8657557f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_5657ab73-443a-4f4f-941a-df026f1a6b40" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_fa0195e7-b67c-4a30-b2da-32a8657557f2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_5657ab73-443a-4f4f-941a-df026f1a6b40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_1e701289-d7bf-4274-9383-ca1c672ccf29" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_5657ab73-443a-4f4f-941a-df026f1a6b40" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_1e701289-d7bf-4274-9383-ca1c672ccf29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_944eaeaa-3de3-44a1-94de-9815eb93ac44" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_944eaeaa-3de3-44a1-94de-9815eb93ac44" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_944eaeaa-3de3-44a1-94de-9815eb93ac44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_944eaeaa-3de3-44a1-94de-9815eb93ac44" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_944eaeaa-3de3-44a1-94de-9815eb93ac44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_588d8249-7710-47ad-8b20-276468fe7494" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_944eaeaa-3de3-44a1-94de-9815eb93ac44" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_588d8249-7710-47ad-8b20-276468fe7494" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_d64b03fd-bcd8-430f-aa44-ea2234971512" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_588d8249-7710-47ad-8b20-276468fe7494" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_d64b03fd-bcd8-430f-aa44-ea2234971512" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6bf03820-efee-409a-b069-afbbf97c7ed4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:to="loc_us-gaap_DebtInstrumentAxis_6bf03820-efee-409a-b069-afbbf97c7ed4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6bf03820-efee-409a-b069-afbbf97c7ed4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6bf03820-efee-409a-b069-afbbf97c7ed4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6bf03820-efee-409a-b069-afbbf97c7ed4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_78a62009-b331-4718-9ca4-932ca06bd4ab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6bf03820-efee-409a-b069-afbbf97c7ed4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_78a62009-b331-4718-9ca4-932ca06bd4ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_c2aa4eeb-0bd9-4e7b-b698-ae7c0e623dbf" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_78a62009-b331-4718-9ca4-932ca06bd4ab" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_c2aa4eeb-0bd9-4e7b-b698-ae7c0e623dbf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_cfe7f14a-a605-4117-a103-53359ebfac9d" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_78a62009-b331-4718-9ca4-932ca06bd4ab" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_cfe7f14a-a605-4117-a103-53359ebfac9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_b83222f2-c67d-4062-a35b-9a65a1672cfb" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_78a62009-b331-4718-9ca4-932ca06bd4ab" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_b83222f2-c67d-4062-a35b-9a65a1672cfb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_de7a57fa-5a42-42c5-b910-8fcfb1a65540" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_343e61be-a851-4d47-83ed-392760a98785" xlink:to="loc_us-gaap_FinancialInstrumentAxis_de7a57fa-5a42-42c5-b910-8fcfb1a65540" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_de7a57fa-5a42-42c5-b910-8fcfb1a65540_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_de7a57fa-5a42-42c5-b910-8fcfb1a65540" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_de7a57fa-5a42-42c5-b910-8fcfb1a65540_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7e45bb4-c4f3-4e95-98d0-e60bf70a756c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_de7a57fa-5a42-42c5-b910-8fcfb1a65540" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7e45bb4-c4f3-4e95-98d0-e60bf70a756c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PrivatelyHeldCompanyMember_4693fb95-b8f9-46d9-9110-5534f4d4f17b" xlink:href="enph-20230930.xsd#enph_PrivatelyHeldCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7e45bb4-c4f3-4e95-98d0-e60bf70a756c" xlink:to="loc_enph_PrivatelyHeldCompanyMember_4693fb95-b8f9-46d9-9110-5534f4d4f17b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_SecuredConvertiblePromissoryNotesMember_01b4c683-6fd3-4274-a3f9-81c235baaf35" xlink:href="enph-20230930.xsd#enph_SecuredConvertiblePromissoryNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7e45bb4-c4f3-4e95-98d0-e60bf70a756c" xlink:to="loc_enph_SecuredConvertiblePromissoryNotesMember_01b4c683-6fd3-4274-a3f9-81c235baaf35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_NonVotingDebtSecurityMember_d460cb62-3a0e-4d21-b92b-7fa97c63657b" xlink:href="enph-20230930.xsd#enph_NonVotingDebtSecurityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7e45bb4-c4f3-4e95-98d0-e60bf70a756c" xlink:to="loc_enph_NonVotingDebtSecurityMember_d460cb62-3a0e-4d21-b92b-7fa97c63657b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/FAIRVALUEMEASUREMENTSDebtSecuritiesScheduleofFairValueDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#FAIRVALUEMEASUREMENTSDebtSecuritiesScheduleofFairValueDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/FAIRVALUEMEASUREMENTSDebtSecuritiesScheduleofFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_229ba564-2ad5-4ab4-899e-bf4c0e187506" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_87dbbb87-a5e7-4029-bced-3408dfa98615" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_229ba564-2ad5-4ab4-899e-bf4c0e187506" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_87dbbb87-a5e7-4029-bced-3408dfa98615" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4dce3547-4656-4cf7-9009-3ad00d4eaab0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_87dbbb87-a5e7-4029-bced-3408dfa98615" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4dce3547-4656-4cf7-9009-3ad00d4eaab0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_a0711dcd-c9d9-4393-8af1-3a0d9fd6a800" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_87dbbb87-a5e7-4029-bced-3408dfa98615" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_a0711dcd-c9d9-4393-8af1-3a0d9fd6a800" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_57261d89-7ec4-47de-883b-c18c3b82747e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_87dbbb87-a5e7-4029-bced-3408dfa98615" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_57261d89-7ec4-47de-883b-c18c3b82747e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_1bcdc677-9b4d-4ba2-aadd-4aab8ebfc089" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_79993cec-6e4c-444b-804f-00172b99bbf1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_229ba564-2ad5-4ab4-899e-bf4c0e187506" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_79993cec-6e4c-444b-804f-00172b99bbf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_bb7a075a-198f-4a67-96fd-068904f7319f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_79993cec-6e4c-444b-804f-00172b99bbf1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_bb7a075a-198f-4a67-96fd-068904f7319f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bb7a075a-198f-4a67-96fd-068904f7319f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_bb7a075a-198f-4a67-96fd-068904f7319f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bb7a075a-198f-4a67-96fd-068904f7319f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f02a6435-6af0-4c25-9147-70a06ab36e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_bb7a075a-198f-4a67-96fd-068904f7319f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f02a6435-6af0-4c25-9147-70a06ab36e7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_601f2877-b3ac-441b-bdbf-fb6a9cc866c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f02a6435-6af0-4c25-9147-70a06ab36e7d" xlink:to="loc_us-gaap_DebtSecuritiesMember_601f2877-b3ac-441b-bdbf-fb6a9cc866c1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/FAIRVALUEMEASUREMENTSScheduleofChangesinNonfinancialLiabilitiesRelatedtoWarrantObligationsMeasuredatFairValueonaRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#FAIRVALUEMEASUREMENTSScheduleofChangesinNonfinancialLiabilitiesRelatedtoWarrantObligationsMeasuredatFairValueonaRecurringBasisUsingSignificantUnobservableInputsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/FAIRVALUEMEASUREMENTSScheduleofChangesinNonfinancialLiabilitiesRelatedtoWarrantObligationsMeasuredatFairValueonaRecurringBasisUsingSignificantUnobservableInputsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_4af4b74b-7596-45d0-b090-02f141b62ef7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_4af4b74b-7596-45d0-b090-02f141b62ef7" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_07488ccd-d7dc-40c8-bbaf-e693542768d3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_07488ccd-d7dc-40c8-bbaf-e693542768d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued_0d704ace-83d0-4d4c-b72a-15db75b8595c" xlink:href="enph-20230930.xsd#enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisWarrantiesIssued_0d704ace-83d0-4d4c-b72a-15db75b8595c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeInEstimate_631b2347-1cea-4833-b88c-0cd3d3466f9d" xlink:href="enph-20230930.xsd#enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeInEstimate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityChangeInEstimate_631b2347-1cea-4833-b88c-0cd3d3466f9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_d26cb75d-8406-451f-912d-6b2e98dd20f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_d26cb75d-8406-451f-912d-6b2e98dd20f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_5d848ca6-b072-4ffa-807b-95944ca7520c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_5d848ca6-b072-4ffa-807b-95944ca7520c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_StandardProductWarrantyAccrualChangeInDiscountRate_581162b5-1094-4c55-892d-4934a07de2b2" xlink:href="enph-20230930.xsd#enph_StandardProductWarrantyAccrualChangeInDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_enph_StandardProductWarrantyAccrualChangeInDiscountRate_581162b5-1094-4c55-892d-4934a07de2b2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIncreaseDecreaseInOther_d3351ad2-6d6c-4061-a616-7dc365ec08f2" xlink:href="enph-20230930.xsd#enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIncreaseDecreaseInOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7eb5956e-51ed-4356-a7f3-3654dfd66bde" xlink:to="loc_enph_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIncreaseDecreaseInOther_d3351ad2-6d6c-4061-a616-7dc365ec08f2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_a9eb9574-debf-4920-ad6c-b1d34961adc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_ba1422d9-a415-4f09-880a-53778cabe12f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_4af4b74b-7596-45d0-b090-02f141b62ef7" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_ba1422d9-a415-4f09-880a-53778cabe12f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_47cf868b-e022-4fe2-b354-dfbbbfa88cc7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_ba1422d9-a415-4f09-880a-53778cabe12f" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_47cf868b-e022-4fe2-b354-dfbbbfa88cc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_47cf868b-e022-4fe2-b354-dfbbbfa88cc7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_47cf868b-e022-4fe2-b354-dfbbbfa88cc7" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_47cf868b-e022-4fe2-b354-dfbbbfa88cc7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_635af81b-e269-4a29-9326-bea0f436359c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_47cf868b-e022-4fe2-b354-dfbbbfa88cc7" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_635af81b-e269-4a29-9326-bea0f436359c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_c6d7d177-5a9e-4b3f-9a77-97662f478872" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_635af81b-e269-4a29-9326-bea0f436359c" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_c6d7d177-5a9e-4b3f-9a77-97662f478872" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_2fde6bce-625a-413f-854c-43c94972e656" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_ba1422d9-a415-4f09-880a-53778cabe12f" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_2fde6bce-625a-413f-854c-43c94972e656" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2fde6bce-625a-413f-854c-43c94972e656_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_2fde6bce-625a-413f-854c-43c94972e656" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2fde6bce-625a-413f-854c-43c94972e656_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_bc1b0825-b010-453e-bb4b-1223220893bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_2fde6bce-625a-413f-854c-43c94972e656" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_bc1b0825-b010-453e-bb4b-1223220893bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_beac43d6-60ef-4636-8537-8031480d8785" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_bc1b0825-b010-453e-bb4b-1223220893bb" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_beac43d6-60ef-4636-8537-8031480d8785" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8a4877e8-f350-4eec-8e9c-971deb689a3f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_ba1422d9-a415-4f09-880a-53778cabe12f" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8a4877e8-f350-4eec-8e9c-971deb689a3f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8a4877e8-f350-4eec-8e9c-971deb689a3f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8a4877e8-f350-4eec-8e9c-971deb689a3f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8a4877e8-f350-4eec-8e9c-971deb689a3f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24b0abb-ec4e-43cd-9839-777a2e064b3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8a4877e8-f350-4eec-8e9c-971deb689a3f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24b0abb-ec4e-43cd-9839-777a2e064b3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_74fa88e2-2519-4290-94c8-7e59ab7d2c76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24b0abb-ec4e-43cd-9839-777a2e064b3c" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_74fa88e2-2519-4290-94c8-7e59ab7d2c76" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/FAIRVALUEMEASUREMENTSSummaryofSignificantUnobservableInputsusedintheFairValueMeasurementofLiabilitiesDesignatedasLevel3Details" xlink:type="simple" xlink:href="enph-20230930.xsd#FAIRVALUEMEASUREMENTSSummaryofSignificantUnobservableInputsusedintheFairValueMeasurementofLiabilitiesDesignatedasLevel3Details"/>
  <link:definitionLink xlink:role="http://enphase.com/role/FAIRVALUEMEASUREMENTSSummaryofSignificantUnobservableInputsusedintheFairValueMeasurementofLiabilitiesDesignatedasLevel3Details" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_f1d157ee-c1e1-4168-9040-2821aa8e74d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ProductWarrantyObligationsMeasurementInput_0483aa76-5bcb-4809-b2be-48b11432d397" xlink:href="enph-20230930.xsd#enph_ProductWarrantyObligationsMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_f1d157ee-c1e1-4168-9040-2821aa8e74d2" xlink:to="loc_enph_ProductWarrantyObligationsMeasurementInput_0483aa76-5bcb-4809-b2be-48b11432d397" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_f1d157ee-c1e1-4168-9040-2821aa8e74d2" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_b2300bcc-dd8f-4be6-9124-27a152848d83" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_b2300bcc-dd8f-4be6-9124-27a152848d83" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_b2300bcc-dd8f-4be6-9124-27a152848d83_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_b2300bcc-dd8f-4be6-9124-27a152848d83" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_b2300bcc-dd8f-4be6-9124-27a152848d83_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_905583e5-c330-430f-830d-714020d14d01" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_b2300bcc-dd8f-4be6-9124-27a152848d83" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_905583e5-c330-430f-830d-714020d14d01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_MeasurementInputProfitElementAndRiskPremiumMember_c82fc652-60eb-445f-8ece-e46aa94f9702" xlink:href="enph-20230930.xsd#enph_MeasurementInputProfitElementAndRiskPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_905583e5-c330-430f-830d-714020d14d01" xlink:to="loc_enph_MeasurementInputProfitElementAndRiskPremiumMember_c82fc652-60eb-445f-8ece-e46aa94f9702" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputEntityCreditRiskMember_b7d2b6b9-b412-4b03-824a-52d66b59286d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputEntityCreditRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_905583e5-c330-430f-830d-714020d14d01" xlink:to="loc_us-gaap_MeasurementInputEntityCreditRiskMember_b7d2b6b9-b412-4b03-824a-52d66b59286d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6976fce8-1dda-4a81-8775-9798462f3335" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6976fce8-1dda-4a81-8775-9798462f3335" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_6976fce8-1dda-4a81-8775-9798462f3335_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6976fce8-1dda-4a81-8775-9798462f3335" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_6976fce8-1dda-4a81-8775-9798462f3335_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_7e6b64ee-298c-4e78-9021-02f2a7277bb0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_6976fce8-1dda-4a81-8775-9798462f3335" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_7e6b64ee-298c-4e78-9021-02f2a7277bb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_95d83ede-07d8-4076-90a5-361db1edb7f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_7e6b64ee-298c-4e78-9021-02f2a7277bb0" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_95d83ede-07d8-4076-90a5-361db1edb7f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d104328e-2abe-4379-8363-9bc52f0f841e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7b8f3ea0-bd85-4bdd-92d4-adee18f4e7cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d104328e-2abe-4379-8363-9bc52f0f841e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_f893f8ff-b2b2-4d85-8ee9-73d76474c497" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d104328e-2abe-4379-8363-9bc52f0f841e" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_f893f8ff-b2b2-4d85-8ee9-73d76474c497" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_d29fbeaf-1f1e-463e-b214-48d678a31baa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_0b4f9111-adea-41ee-9a68-038fc330d050" xlink:to="loc_us-gaap_FinancialInstrumentAxis_d29fbeaf-1f1e-463e-b214-48d678a31baa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d29fbeaf-1f1e-463e-b214-48d678a31baa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d29fbeaf-1f1e-463e-b214-48d678a31baa" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d29fbeaf-1f1e-463e-b214-48d678a31baa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d195821f-2857-4f05-8e67-a660171161fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d29fbeaf-1f1e-463e-b214-48d678a31baa" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d195821f-2857-4f05-8e67-a660171161fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_d03292e7-f396-4ac5-ac8e-ea67c4f0cd34" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantyRightsAndObligationsFairValueOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d195821f-2857-4f05-8e67-a660171161fe" xlink:to="loc_us-gaap_WarrantyRightsAndObligationsFairValueOptionMember_d03292e7-f396-4ac5-ac8e-ea67c4f0cd34" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTLongtermdebtDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTLongtermdebtDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTLongtermdebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_6b8cf53f-df62-48a1-96eb-ad4ac4f93b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_6b8cf53f-df62-48a1-96eb-ad4ac4f93b2c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_e71607bd-cf19-4901-9a47-daada8221cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_e71607bd-cf19-4901-9a47-daada8221cd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_cb6ccc29-a0c1-474c-bafd-5bc8eb0dc4e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_cb6ccc29-a0c1-474c-bafd-5bc8eb0dc4e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_98fdc9d5-93b9-4589-b956-d81dd304a77e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_LongTermDebt_98fdc9d5-93b9-4589-b956-d81dd304a77e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_3fd14505-7352-44dc-aec9-0597d4faac48" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_LongTermDebtCurrent_3fd14505-7352-44dc-aec9-0597d4faac48" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_ae3d7cb4-775a-4061-b2de-f7916b8c8dc4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_ae3d7cb4-775a-4061-b2de-f7916b8c8dc4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_456e1a5f-4bd2-4059-9eb7-178b7f7caed6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_52e0b823-f592-44f6-80ca-7f0cc84231ae" xlink:to="loc_us-gaap_DebtInstrumentTable_456e1a5f-4bd2-4059-9eb7-178b7f7caed6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_456e1a5f-4bd2-4059-9eb7-178b7f7caed6" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4d3917ca-bd36-4b15-a2ac-90905904ede3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_8242a2b6-069c-4f4d-9f0f-9ed709c06ba2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4d3917ca-bd36-4b15-a2ac-90905904ede3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_f9eb4d2d-5dd1-4ea9-8313-9085066cbeaa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_4d3917ca-bd36-4b15-a2ac-90905904ede3" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_f9eb4d2d-5dd1-4ea9-8313-9085066cbeaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_a6e4f4ba-be40-4f5b-abcf-72f7df653d96" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_456e1a5f-4bd2-4059-9eb7-178b7f7caed6" xlink:to="loc_us-gaap_DebtInstrumentAxis_a6e4f4ba-be40-4f5b-abcf-72f7df653d96" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_a6e4f4ba-be40-4f5b-abcf-72f7df653d96_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_a6e4f4ba-be40-4f5b-abcf-72f7df653d96" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_a6e4f4ba-be40-4f5b-abcf-72f7df653d96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_a6e4f4ba-be40-4f5b-abcf-72f7df653d96" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_ebf65d24-ccc9-42e6-9be2-c37d2f317fbc" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_ebf65d24-ccc9-42e6-9be2-c37d2f317fbc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_3339b572-7fb9-481f-bebf-6dcf68c71ef2" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_3339b572-7fb9-481f-bebf-6dcf68c71ef2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_076510f4-f8d4-4a3a-bdc2-3c20ed3038b6" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_076510f4-f8d4-4a3a-bdc2-3c20ed3038b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2023Member_5a020a29-2990-426f-847e-933715b09af1" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f38b4f1b-f258-4392-b569-28dc6fbc8d3e" xlink:to="loc_enph_ConvertibleSeniorNotesDue2023Member_5a020a29-2990-426f-847e-933715b09af1" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTScheduleofInterestCostRecognizedInStatementsOfOperationsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTScheduleofInterestCostRecognizedInStatementsOfOperationsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTScheduleofInterestCostRecognizedInStatementsOfOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebtExcludingAmortization_16141d0a-9503-429e-ba82-373a3deace57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseDebtExcludingAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:to="loc_us-gaap_InterestExpenseDebtExcludingAmortization_16141d0a-9503-429e-ba82-373a3deace57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDebtDiscountPremium_2101c2fc-7cb9-4e29-92bb-b849d0582834" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:to="loc_us-gaap_AmortizationOfDebtDiscountPremium_2101c2fc-7cb9-4e29-92bb-b849d0582834" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_65f6e0ef-3d7e-4271-b82d-0c35c3f1d1d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_65f6e0ef-3d7e-4271-b82d-0c35c3f1d1d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_47257f28-26ec-405a-828f-0252695fdc76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:to="loc_us-gaap_InterestExpenseDebt_47257f28-26ec-405a-828f-0252695fdc76" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_95d737b0-2031-4b44-be17-7397d9d08c1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_8293877f-4991-498e-8a26-1c7d48a70fdb" xlink:to="loc_us-gaap_DebtInstrumentTable_95d737b0-2031-4b44-be17-7397d9d08c1a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_6c62d2bb-9330-4cd8-ac19-61ca98d0d121" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_95d737b0-2031-4b44-be17-7397d9d08c1a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_6c62d2bb-9330-4cd8-ac19-61ca98d0d121" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6c62d2bb-9330-4cd8-ac19-61ca98d0d121_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6c62d2bb-9330-4cd8-ac19-61ca98d0d121" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6c62d2bb-9330-4cd8-ac19-61ca98d0d121_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a6aee692-7513-417d-9ee8-ce50a8cc8d24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6c62d2bb-9330-4cd8-ac19-61ca98d0d121" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a6aee692-7513-417d-9ee8-ce50a8cc8d24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_97fa4386-5298-4d22-a44b-8d7a7659b9a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_a6aee692-7513-417d-9ee8-ce50a8cc8d24" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_97fa4386-5298-4d22-a44b-8d7a7659b9a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4ba97b0f-0d83-4422-b065-c02cb4e93396" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_95d737b0-2031-4b44-be17-7397d9d08c1a" xlink:to="loc_us-gaap_DebtInstrumentAxis_4ba97b0f-0d83-4422-b065-c02cb4e93396" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4ba97b0f-0d83-4422-b065-c02cb4e93396_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4ba97b0f-0d83-4422-b065-c02cb4e93396" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4ba97b0f-0d83-4422-b065-c02cb4e93396_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4ba97b0f-0d83-4422-b065-c02cb4e93396" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_f834e9ce-6f97-484c-82e0-1cede92e434b" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_f834e9ce-6f97-484c-82e0-1cede92e434b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_76dd59c0-4a2c-435d-8e55-0aabfc1e5b13" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_76dd59c0-4a2c-435d-8e55-0aabfc1e5b13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_7cd9da88-0446-487a-8350-a8b64e8fa435" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_7cd9da88-0446-487a-8350-a8b64e8fa435" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2023Member_d56c32fd-31f7-4628-99d4-c1e438e6d596" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_decd081b-6f43-45c6-8ceb-fb3e93b6632c" xlink:to="loc_enph_ConvertibleSeniorNotesDue2023Member_d56c32fd-31f7-4628-99d4-c1e438e6d596" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2028NarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTConvertibleSeniorNotesduein2028NarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2028NarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_92fe0a86-2f36-4848-85e0-fbb67aa1c9ee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_92fe0a86-2f36-4848-85e0-fbb67aa1c9ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a6a1d7f2-2181-43cf-8590-96946fe80a7b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a6a1d7f2-2181-43cf-8590-96946fe80a7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_63ef84b6-7a68-451f-9f15-e66dc6c8f035" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_63ef84b6-7a68-451f-9f15-e66dc6c8f035" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_6fe74468-3ffc-47ed-b223-026278c6813d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_6fe74468-3ffc-47ed-b223-026278c6813d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_fd5aa552-89ae-4981-9334-a8788026e456" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_fd5aa552-89ae-4981-9334-a8788026e456" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_7fcaf7b8-4b8e-4198-ba09-515462a759c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_7fcaf7b8-4b8e-4198-ba09-515462a759c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_7be8c97e-51d1-4f4b-a037-5887e13185e0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_7be8c97e-51d1-4f4b-a037-5887e13185e0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_3308e821-1a47-4b64-970e-cfb04de26605" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_3308e821-1a47-4b64-970e-cfb04de26605" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_3365d0c6-47f3-4f86-8816-ab3e8677fff8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_3365d0c6-47f3-4f86-8816-ab3e8677fff8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_f43e53e3-ea00-4308-8054-43d1c771a3b4" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_f43e53e3-ea00-4308-8054-43d1c771a3b4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_b814a12a-0a5a-4cc1-9000-a1a98343adb8" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_b814a12a-0a5a-4cc1-9000-a1a98343adb8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayable_f1a9e2d0-d599-45f2-9235-a3b7e93dc11d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_ConvertibleNotesPayable_f1a9e2d0-d599-45f2-9235-a3b7e93dc11d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMeasurementInput_f8e86e37-5c8b-4ef8-9e07-9837bf670698" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentMeasurementInput_f8e86e37-5c8b-4ef8-9e07-9837bf670698" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent_549fa1cc-673f-4fbf-a360-b2e0a3e87dba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent_549fa1cc-673f-4fbf-a360-b2e0a3e87dba" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_a8f0d12f-2995-40b1-8f3f-504c5a4ec8cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_a8f0d12f-2995-40b1-8f3f-504c5a4ec8cb" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_7bcde3b0-f611-4f0b-8a14-347eac49e402" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_7bcde3b0-f611-4f0b-8a14-347eac49e402" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_89844465-1e9d-45c9-8c09-14e535265a0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_89844465-1e9d-45c9-8c09-14e535265a0d" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtIssuanceCostsAllocatedToCapital_9c4800f7-e1bc-427b-8ce6-1531a64376e5" xlink:href="enph-20230930.xsd#enph_DebtIssuanceCostsAllocatedToCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_enph_DebtIssuanceCostsAllocatedToCapital_9c4800f7-e1bc-427b-8ce6-1531a64376e5" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_fcb74c35-dd25-4297-9883-6e4f137b0e14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_AdditionalPaidInCapital_fcb74c35-dd25-4297-9883-6e4f137b0e14" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebt_d509fc51-989a-4e1b-91c9-09ddf8ae9df1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_ConvertibleDebt_d509fc51-989a-4e1b-91c9-09ddf8ae9df1" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_d76be0f1-1f5b-4a0d-9f82-fdf093948aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_d76be0f1-1f5b-4a0d-9f82-fdf093948aa0" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_e33cc097-76d4-4bc8-a05f-cfddc10be668" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_e33cc097-76d4-4bc8-a05f-cfddc10be668" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleConversionShares_77d33e91-b9ec-46f5-81aa-e6658b5deb91" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleConversionShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_enph_DebtInstrumentConvertibleConversionShares_77d33e91-b9ec-46f5-81aa-e6658b5deb91" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForHedgeFinancingActivities_14151e7e-ab2f-4970-9ed4-28d6fb36f144" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForHedgeFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_PaymentsForHedgeFinancingActivities_14151e7e-ab2f-4970-9ed4-28d6fb36f144" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_f17aa75b-9e0c-478a-a2b5-1c1cd7b5e086" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_f17aa75b-9e0c-478a-a2b5-1c1cd7b5e086" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_160162e2-4b34-4786-9ed6-48c3ceb327cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_160162e2-4b34-4786-9ed6-48c3ceb327cd" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ae556628-1770-420b-a3f3-edcdf5df78f7" xlink:to="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_fdecff72-9d0c-41c3-a92d-4f02ef35431c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_fdecff72-9d0c-41c3-a92d-4f02ef35431c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_fdecff72-9d0c-41c3-a92d-4f02ef35431c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_fdecff72-9d0c-41c3-a92d-4f02ef35431c" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_fdecff72-9d0c-41c3-a92d-4f02ef35431c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_12635902-c699-4785-a66b-602f9b065c7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_fdecff72-9d0c-41c3-a92d-4f02ef35431c" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_12635902-c699-4785-a66b-602f9b065c7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_9e19b4f9-281b-4ac9-b23a-d63866a39535" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_12635902-c699-4785-a66b-602f9b065c7c" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_9e19b4f9-281b-4ac9-b23a-d63866a39535" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_d7f1e8a6-f587-4dd3-a158-7521e28c0c17" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_12635902-c699-4785-a66b-602f9b065c7c" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_d7f1e8a6-f587-4dd3-a158-7521e28c0c17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_b38d913a-8c5c-478e-9f5b-532ed1028098" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_b38d913a-8c5c-478e-9f5b-532ed1028098" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b38d913a-8c5c-478e-9f5b-532ed1028098_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b38d913a-8c5c-478e-9f5b-532ed1028098" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b38d913a-8c5c-478e-9f5b-532ed1028098_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_410a7f89-af17-4db6-9bd7-0279db8fb1c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b38d913a-8c5c-478e-9f5b-532ed1028098" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_410a7f89-af17-4db6-9bd7-0279db8fb1c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_e422531b-72bb-47ba-9d6e-77e16c72dd38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_410a7f89-af17-4db6-9bd7-0279db8fb1c7" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_e422531b-72bb-47ba-9d6e-77e16c72dd38" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_89bcf304-0ef4-40ca-a19f-7590c92c19ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_us-gaap_DebtInstrumentAxis_89bcf304-0ef4-40ca-a19f-7590c92c19ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_89bcf304-0ef4-40ca-a19f-7590c92c19ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_89bcf304-0ef4-40ca-a19f-7590c92c19ae" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_89bcf304-0ef4-40ca-a19f-7590c92c19ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_58db5f1e-2842-4fc0-beea-484724dcaa06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_89bcf304-0ef4-40ca-a19f-7590c92c19ae" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_58db5f1e-2842-4fc0-beea-484724dcaa06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_614e7b6f-2f2a-4faa-a811-62bf25d27f3c" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_58db5f1e-2842-4fc0-beea-484724dcaa06" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_614e7b6f-2f2a-4faa-a811-62bf25d27f3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_f43e94c0-d16a-4274-8c79-a4057be21e5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_f43e94c0-d16a-4274-8c79-a4057be21e5e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_f43e94c0-d16a-4274-8c79-a4057be21e5e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_f43e94c0-d16a-4274-8c79-a4057be21e5e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_f43e94c0-d16a-4274-8c79-a4057be21e5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_4e387d52-ea64-4fcd-b2f6-e0f627655002" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_f43e94c0-d16a-4274-8c79-a4057be21e5e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_4e387d52-ea64-4fcd-b2f6-e0f627655002" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_adc73cd3-3f82-4902-afb6-b4ae0413c060" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_4e387d52-ea64-4fcd-b2f6-e0f627655002" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_adc73cd3-3f82-4902-afb6-b4ae0413c060" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6914fd8-7f54-4b32-a3ae-31643f159a53" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6914fd8-7f54-4b32-a3ae-31643f159a53" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a6914fd8-7f54-4b32-a3ae-31643f159a53_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6914fd8-7f54-4b32-a3ae-31643f159a53" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a6914fd8-7f54-4b32-a3ae-31643f159a53_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f9ce9c39-8ee2-43de-9c64-8f3e80f193a3" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6914fd8-7f54-4b32-a3ae-31643f159a53" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f9ce9c39-8ee2-43de-9c64-8f3e80f193a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_53a4ce0b-1079-41e9-928d-14d462298887" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f9ce9c39-8ee2-43de-9c64-8f3e80f193a3" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_53a4ce0b-1079-41e9-928d-14d462298887" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3fa22204-c3d0-4d18-9f32-5637b3505214" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f78989bf-fbe0-40bf-b81c-b1e82c2af543" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3fa22204-c3d0-4d18-9f32-5637b3505214" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_3fa22204-c3d0-4d18-9f32-5637b3505214_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3fa22204-c3d0-4d18-9f32-5637b3505214" xlink:to="loc_us-gaap_TypeOfAdoptionMember_3fa22204-c3d0-4d18-9f32-5637b3505214_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_40cb490a-62f4-4a45-8175-1e8309dac39f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3fa22204-c3d0-4d18-9f32-5637b3505214" xlink:to="loc_us-gaap_TypeOfAdoptionMember_40cb490a-62f4-4a45-8175-1e8309dac39f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate202006Member_249547f9-0fd6-4e60-a53e-10b67719d200" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate202006Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_40cb490a-62f4-4a45-8175-1e8309dac39f" xlink:to="loc_us-gaap_AccountingStandardsUpdate202006Member_249547f9-0fd6-4e60-a53e-10b67719d200" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2026NarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTConvertibleSeniorNotesduein2026NarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2026NarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_b4edcbb6-96cc-46cf-a060-017a89b470a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_b4edcbb6-96cc-46cf-a060-017a89b470a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_90f2d6b6-dc67-49d4-aae2-fd0094d6018a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_90f2d6b6-dc67-49d4-aae2-fd0094d6018a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_78518725-5559-4f91-b1e3-4b320466e86e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_78518725-5559-4f91-b1e3-4b320466e86e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_7b66d679-ee54-4ff2-b748-d134819cc3a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_7b66d679-ee54-4ff2-b748-d134819cc3a9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_e0ac886f-87eb-440e-b457-016fc30cd857" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_e0ac886f-87eb-440e-b457-016fc30cd857" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_8645fdc1-7bb1-482f-b97f-978396c809ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_8645fdc1-7bb1-482f-b97f-978396c809ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_7757b2af-2bf6-4a0e-bc86-d40ae66fdb82" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_7757b2af-2bf6-4a0e-bc86-d40ae66fdb82" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_ce62f404-b431-445f-8578-e61f460c6753" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_ce62f404-b431-445f-8578-e61f460c6753" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_46a01b93-5463-4ecc-8616-5162f85171b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_46a01b93-5463-4ecc-8616-5162f85171b6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_5dfd1770-1498-4124-8791-bda62d19371e" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_5dfd1770-1498-4124-8791-bda62d19371e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_1c1fe974-53e6-4202-b148-80e7dfda88a2" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_1c1fe974-53e6-4202-b148-80e7dfda88a2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayable_804c17a8-c968-4619-9ebf-d440bbc261cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_ConvertibleNotesPayable_804c17a8-c968-4619-9ebf-d440bbc261cd" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMeasurementInput_e5bdc98b-108a-45ec-81ba-d7a65cb8a865" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentMeasurementInput_e5bdc98b-108a-45ec-81ba-d7a65cb8a865" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent_6629dd01-4642-4f70-8328-6ebdaadc49b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent_6629dd01-4642-4f70-8328-6ebdaadc49b7" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_dc52ef58-6200-4b6d-99ce-5f799bfc4208" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_dc52ef58-6200-4b6d-99ce-5f799bfc4208" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_0baf7796-783c-440e-8a1c-d2b0590a8c50" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_0baf7796-783c-440e-8a1c-d2b0590a8c50" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtIssuanceCostsAllocatedToCapital_e9af7c37-5d97-401d-b680-4428b878ba96" xlink:href="enph-20230930.xsd#enph_DebtIssuanceCostsAllocatedToCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_enph_DebtIssuanceCostsAllocatedToCapital_e9af7c37-5d97-401d-b680-4428b878ba96" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_b55b1e5e-8b70-4e44-8395-9a3004b82812" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_AdditionalPaidInCapital_b55b1e5e-8b70-4e44-8395-9a3004b82812" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebt_a65fceca-7a15-4bb9-9e61-7b689157afab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_ConvertibleDebt_a65fceca-7a15-4bb9-9e61-7b689157afab" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_524f7cc0-1e8b-41c1-9e7f-51ea8007b652" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_524f7cc0-1e8b-41c1-9e7f-51ea8007b652" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_46003aff-1848-433e-92c5-2a633923e3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_46003aff-1848-433e-92c5-2a633923e3d9" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleConversionShares_6b79f605-8d9c-4fd6-82cb-f52e8ee97b0b" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleConversionShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_enph_DebtInstrumentConvertibleConversionShares_6b79f605-8d9c-4fd6-82cb-f52e8ee97b0b" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForHedgeFinancingActivities_0a47dd52-673d-4764-9ff9-e168767968c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForHedgeFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_PaymentsForHedgeFinancingActivities_0a47dd52-673d-4764-9ff9-e168767968c4" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_37f67649-3a78-49e4-86e0-67381caff873" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_37f67649-3a78-49e4-86e0-67381caff873" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_298004aa-640c-40ec-9a7a-d822fe2d574a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_298004aa-640c-40ec-9a7a-d822fe2d574a" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_3ea86dfc-db45-418b-968f-59b406a03d83" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_3ea86dfc-db45-418b-968f-59b406a03d83" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1d789d16-7f37-43c1-b114-9644d86b3077" xlink:to="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_ba21b717-21e3-4c4b-b76e-d053c4c94635" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_ba21b717-21e3-4c4b-b76e-d053c4c94635" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_ba21b717-21e3-4c4b-b76e-d053c4c94635_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_ba21b717-21e3-4c4b-b76e-d053c4c94635" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_ba21b717-21e3-4c4b-b76e-d053c4c94635_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_2e30310e-34aa-4ea7-9e3d-a1965a22f1e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_ba21b717-21e3-4c4b-b76e-d053c4c94635" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_2e30310e-34aa-4ea7-9e3d-a1965a22f1e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_f40f7bf0-5522-4c80-913a-7c176d1543b3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_2e30310e-34aa-4ea7-9e3d-a1965a22f1e9" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_f40f7bf0-5522-4c80-913a-7c176d1543b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_70039e02-5d41-40bd-98da-f1d3976d731a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_2e30310e-34aa-4ea7-9e3d-a1965a22f1e9" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_70039e02-5d41-40bd-98da-f1d3976d731a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_a817cd2c-1925-47d3-9f2e-cc779b891708" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_a817cd2c-1925-47d3-9f2e-cc779b891708" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a817cd2c-1925-47d3-9f2e-cc779b891708_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a817cd2c-1925-47d3-9f2e-cc779b891708" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a817cd2c-1925-47d3-9f2e-cc779b891708_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3838f3b1-b1e8-4f47-aa31-c4c5276fd7a6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a817cd2c-1925-47d3-9f2e-cc779b891708" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3838f3b1-b1e8-4f47-aa31-c4c5276fd7a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_00ae909c-4b21-472a-a7a8-7c324ed936e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3838f3b1-b1e8-4f47-aa31-c4c5276fd7a6" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_00ae909c-4b21-472a-a7a8-7c324ed936e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4d95e0fe-6755-4cea-93ec-eee35ebc5587" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_us-gaap_DebtInstrumentAxis_4d95e0fe-6755-4cea-93ec-eee35ebc5587" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4d95e0fe-6755-4cea-93ec-eee35ebc5587_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4d95e0fe-6755-4cea-93ec-eee35ebc5587" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4d95e0fe-6755-4cea-93ec-eee35ebc5587_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_09f974b5-1862-4217-a37a-fa07e842eb5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4d95e0fe-6755-4cea-93ec-eee35ebc5587" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_09f974b5-1862-4217-a37a-fa07e842eb5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_dedde86f-99b4-426f-8601-a3f23f5874dd" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_09f974b5-1862-4217-a37a-fa07e842eb5e" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_dedde86f-99b4-426f-8601-a3f23f5874dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_e10c57d3-27fd-4b76-8668-27d0d7fd8881" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_e10c57d3-27fd-4b76-8668-27d0d7fd8881" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_e10c57d3-27fd-4b76-8668-27d0d7fd8881_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_e10c57d3-27fd-4b76-8668-27d0d7fd8881" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_e10c57d3-27fd-4b76-8668-27d0d7fd8881_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_9aa8cad8-84ba-48d0-a36e-10eaa8707435" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_e10c57d3-27fd-4b76-8668-27d0d7fd8881" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_9aa8cad8-84ba-48d0-a36e-10eaa8707435" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_4972cf02-e289-4634-9876-f3a89e02310b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_9aa8cad8-84ba-48d0-a36e-10eaa8707435" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_4972cf02-e289-4634-9876-f3a89e02310b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_545d58ab-ede2-480d-853a-eb6df4497cb6" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_31bec1ab-5448-4ddf-aff7-53f6a4bfad1b" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_545d58ab-ede2-480d-853a-eb6df4497cb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_838831bf-f112-493c-bd93-330a51fffc66" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_545d58ab-ede2-480d-853a-eb6df4497cb6" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_838831bf-f112-493c-bd93-330a51fffc66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_7c3b5a55-c133-44ee-b4f4-330a26f71f0b" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1" xlink:to="loc_us-gaap_TypeOfAdoptionMember_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_3cdf0b5d-7f10-4671-9687-9e254afe1ecc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_af8cdb80-632f-47a3-bc8d-ddc6bafd06b1" xlink:to="loc_us-gaap_TypeOfAdoptionMember_3cdf0b5d-7f10-4671-9687-9e254afe1ecc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate202006Member_96bab254-d38d-4a46-97a9-fc24b0b47880" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate202006Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_3cdf0b5d-7f10-4671-9687-9e254afe1ecc" xlink:to="loc_us-gaap_AccountingStandardsUpdate202006Member_96bab254-d38d-4a46-97a9-fc24b0b47880" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2025NarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTConvertibleSeniorNotesduein2025NarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTConvertibleSeniorNotesduein2025NarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_b39cfa55-33bb-49a0-8f16-c7c960b092a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_b39cfa55-33bb-49a0-8f16-c7c960b092a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_902c25d8-8f29-42c8-a582-b14e5aea3ad5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_902c25d8-8f29-42c8-a582-b14e5aea3ad5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_06812ecf-b8fa-4242-beb2-09f0f431187c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_06812ecf-b8fa-4242-beb2-09f0f431187c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_d39b2a92-227b-4ed5-99c1-651517f47a26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_d39b2a92-227b-4ed5-99c1-651517f47a26" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_e61e4cbc-a2a7-4670-a59e-a1e29d406205" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_e61e4cbc-a2a7-4670-a59e-a1e29d406205" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_8e64c61b-8081-4b31-a0b3-f126daa4bfa0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_8e64c61b-8081-4b31-a0b3-f126daa4bfa0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_44775619-a442-4bd7-bd91-497910722a6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_44775619-a442-4bd7-bd91-497910722a6f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_4d1406cb-f384-4e54-87ea-8a7c8762371f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_4d1406cb-f384-4e54-87ea-8a7c8762371f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_75e81149-e166-4faa-afef-328a71c91866" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtInstrumentConvertibleBusinessDayPeriodAfterMeasurementPeriod_75e81149-e166-4faa-afef-328a71c91866" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_715c731a-0d01-4622-94b8-b7eb9879eccb" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtInstrumentConvertibleMeasurementPeriodPercentageOfStockPriceTrigger_715c731a-0d01-4622-94b8-b7eb9879eccb" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_5e623761-a842-4d15-bc62-ccd32b9e1efc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentConvertibleStockPriceTrigger_5e623761-a842-4d15-bc62-ccd32b9e1efc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_cfde221c-85dd-4087-adca-c4d218949416" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_LongTermDebt_cfde221c-85dd-4087-adca-c4d218949416" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability_9110bc11-541a-4fc7-a6cd-55a743668cc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability_9110bc11-541a-4fc7-a6cd-55a743668cc2" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EmbeddedDerivativeHostContract_d8a72904-8159-4e36-8118-6c0815bffa99" xlink:href="enph-20230930.xsd#enph_EmbeddedDerivativeHostContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_EmbeddedDerivativeHostContract_d8a72904-8159-4e36-8118-6c0815bffa99" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_59423d8e-994a-4b22-883d-18c2498f877d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_59423d8e-994a-4b22-883d-18c2498f877d" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_c1c300d9-4796-44d9-a3be-3718b17343fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_c1c300d9-4796-44d9-a3be-3718b17343fa" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_0b60a317-adde-4f56-a5b3-d864cdf8a988" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_0b60a317-adde-4f56-a5b3-d864cdf8a988" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_5ee3496a-060b-44a2-a0ce-715cfaecd7cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_5ee3496a-060b-44a2-a0ce-715cfaecd7cb" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PaymentsForPartialRepurchaseOfConvertibleDebt_37806110-f642-4c80-af28-7240a65cfd54" xlink:href="enph-20230930.xsd#enph_PaymentsForPartialRepurchaseOfConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_PaymentsForPartialRepurchaseOfConvertibleDebt_37806110-f642-4c80-af28-7240a65cfd54" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_94d4c7d7-927d-4502-a6d9-712240062628" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_94d4c7d7-927d-4502-a6d9-712240062628" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_efe2a90d-35b2-4cd4-97f8-33e5c2625fb1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_efe2a90d-35b2-4cd4-97f8-33e5c2625fb1" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayable_7730f689-52d0-45f3-a1a9-058223d754fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_ConvertibleNotesPayable_7730f689-52d0-45f3-a1a9-058223d754fa" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtConversionResidual_3b6282a1-e218-48a5-bb18-fc5472c30d4b" xlink:href="enph-20230930.xsd#enph_DebtConversionResidual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtConversionResidual_3b6282a1-e218-48a5-bb18-fc5472c30d4b" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InducedConversionOfConvertibleDebtExpense_c135ca08-39ef-498d-b3ab-dc6ae4e26ff2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InducedConversionOfConvertibleDebtExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_InducedConversionOfConvertibleDebtExpense_c135ca08-39ef-498d-b3ab-dc6ae4e26ff2" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMeasurementInput_73adaaf1-c5fe-4d2c-bd21-ad8c9484e83b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentMeasurementInput_73adaaf1-c5fe-4d2c-bd21-ad8c9484e83b" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentRemainingExpectedLife_6a533489-d5fa-4a4a-aedc-112fc92f5c18" xlink:href="enph-20230930.xsd#enph_DebtInstrumentRemainingExpectedLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtInstrumentRemainingExpectedLife_6a533489-d5fa-4a4a-aedc-112fc92f5c18" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WriteOffOfDebtDiscount_2c982b63-f9f7-42c4-917d-f55e90de28a2" xlink:href="enph-20230930.xsd#enph_WriteOffOfDebtDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_WriteOffOfDebtDiscount_2c982b63-f9f7-42c4-917d-f55e90de28a2" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_b68d8c70-a119-4713-a8cb-7622380d0b44" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_b68d8c70-a119-4713-a8cb-7622380d0b44" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnRepurchaseOfDebtInstrument_0ef996fd-3936-4b0a-878f-a58b62a8b07c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnRepurchaseOfDebtInstrument"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_GainLossOnRepurchaseOfDebtInstrument_0ef996fd-3936-4b0a-878f-a58b62a8b07c" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_8edd763f-32d0-4ef8-8848-b5f10ea766e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_8edd763f-32d0-4ef8-8848-b5f10ea766e5" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_9dcef9f3-355b-48cd-abd3-f38f94b4cafe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_LongTermDebtCurrent_9dcef9f3-355b-48cd-abd3-f38f94b4cafe" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_bb5b1ab0-7ba9-4614-8b16-55092e7571bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_bb5b1ab0-7ba9-4614-8b16-55092e7571bf" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_7109c726-95ba-4616-b0ad-42b9b7bb6c7a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_7109c726-95ba-4616-b0ad-42b9b7bb6c7a" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentRemainingDiscountAmortizationPeriod_defc90a7-9f3a-4066-8c77-1edfee26e80e" xlink:href="enph-20230930.xsd#enph_DebtInstrumentRemainingDiscountAmortizationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtInstrumentRemainingDiscountAmortizationPeriod_defc90a7-9f3a-4066-8c77-1edfee26e80e" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_DebtInstrumentConvertibleConversionShares_68f31a84-0dad-4c37-94fd-78146e7b37d6" xlink:href="enph-20230930.xsd#enph_DebtInstrumentConvertibleConversionShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_DebtInstrumentConvertibleConversionShares_68f31a84-0dad-4c37-94fd-78146e7b37d6" xlink:type="arc" order="34"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForHedgeFinancingActivities_ac453084-7b29-4f1c-9e0b-d1de0315d89f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForHedgeFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_PaymentsForHedgeFinancingActivities_ac453084-7b29-4f1c-9e0b-d1de0315d89f" xlink:type="arc" order="35"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_33012cde-679f-403b-9096-cab3ad3d5da7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_33012cde-679f-403b-9096-cab3ad3d5da7" xlink:type="arc" order="36"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_b7094272-c02b-490c-95ee-58a2d18c0de3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_b7094272-c02b-490c-95ee-58a2d18c0de3" xlink:type="arc" order="37"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleNotesHedgeSettlementSharesReceived_dead8c25-7e6c-4f5b-8047-7f60992106c2" xlink:href="enph-20230930.xsd#enph_ConvertibleNotesHedgeSettlementSharesReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_ConvertibleNotesHedgeSettlementSharesReceived_dead8c25-7e6c-4f5b-8047-7f60992106c2" xlink:type="arc" order="38"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_SharesIssuedWarrantsUnwound_23006dfd-8bb8-4177-8ecc-79506ed6c6f8" xlink:href="enph-20230930.xsd#enph_SharesIssuedWarrantsUnwound"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_SharesIssuedWarrantsUnwound_23006dfd-8bb8-4177-8ecc-79506ed6c6f8" xlink:type="arc" order="39"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleNotesHedgeTransactionOptionsOutstanding_d149e459-c46d-4495-b978-db2ce5423203" xlink:href="enph-20230930.xsd#enph_ConvertibleNotesHedgeTransactionOptionsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_enph_ConvertibleNotesHedgeTransactionOptionsOutstanding_d149e459-c46d-4495-b978-db2ce5423203" xlink:type="arc" order="40"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding_8560eb02-2693-431b-9485-109dc7949de4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_ClassOfWarrantOrRightOutstanding_8560eb02-2693-431b-9485-109dc7949de4" xlink:type="arc" order="41"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_eb4b3695-34aa-4cd9-bdc6-c5e85de2450f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_eb4b3695-34aa-4cd9-bdc6-c5e85de2450f" xlink:type="arc" order="42"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_34721454-b280-4c38-9943-119c7e2e82c6" xlink:to="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_16cb8e2e-217c-4f0c-b823-b27c054aea2a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_16cb8e2e-217c-4f0c-b823-b27c054aea2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_16cb8e2e-217c-4f0c-b823-b27c054aea2a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_16cb8e2e-217c-4f0c-b823-b27c054aea2a" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_16cb8e2e-217c-4f0c-b823-b27c054aea2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4c123533-7e94-4531-9e1b-2c808e3aaa0f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_16cb8e2e-217c-4f0c-b823-b27c054aea2a" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4c123533-7e94-4531-9e1b-2c808e3aaa0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_42eff6ab-b32f-4271-acb8-041e5737e795" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4c123533-7e94-4531-9e1b-2c808e3aaa0f" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_42eff6ab-b32f-4271-acb8-041e5737e795" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_5f5f142d-eaca-4a0c-8fad-8e4c7217dcbf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4c123533-7e94-4531-9e1b-2c808e3aaa0f" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_5f5f142d-eaca-4a0c-8fad-8e4c7217dcbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_839b98d4-f2ee-4916-8e6c-3f125ea99019" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_839b98d4-f2ee-4916-8e6c-3f125ea99019" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_839b98d4-f2ee-4916-8e6c-3f125ea99019_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_839b98d4-f2ee-4916-8e6c-3f125ea99019" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_839b98d4-f2ee-4916-8e6c-3f125ea99019_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_75246dbe-bfac-42db-9a2c-42767e627067" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_839b98d4-f2ee-4916-8e6c-3f125ea99019" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_75246dbe-bfac-42db-9a2c-42767e627067" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_3c1f80e7-3da4-4906-a2e9-858193c4c185" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_75246dbe-bfac-42db-9a2c-42767e627067" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_3c1f80e7-3da4-4906-a2e9-858193c4c185" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_684a9193-6837-40c1-a965-c1b1ec4c640d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:to="loc_us-gaap_DebtInstrumentAxis_684a9193-6837-40c1-a965-c1b1ec4c640d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_684a9193-6837-40c1-a965-c1b1ec4c640d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_684a9193-6837-40c1-a965-c1b1ec4c640d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_684a9193-6837-40c1-a965-c1b1ec4c640d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_19829334-92a9-49f5-b747-8f7311083f06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_684a9193-6837-40c1-a965-c1b1ec4c640d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_19829334-92a9-49f5-b747-8f7311083f06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_4ef32eac-9b1a-42d3-ad48-73994cfbc633" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_19829334-92a9-49f5-b747-8f7311083f06" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_4ef32eac-9b1a-42d3-ad48-73994cfbc633" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_42863a4e-8150-4eb1-a104-47253b618bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9d78265e-bef9-46d1-abdf-b2cf45020de9" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_42863a4e-8150-4eb1-a104-47253b618bf2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_42863a4e-8150-4eb1-a104-47253b618bf2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_42863a4e-8150-4eb1-a104-47253b618bf2" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_42863a4e-8150-4eb1-a104-47253b618bf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_c134a5f4-5078-4ba7-b937-a0bef090ef0a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_42863a4e-8150-4eb1-a104-47253b618bf2" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_c134a5f4-5078-4ba7-b937-a0bef090ef0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_35909d16-adfb-4af6-a2ba-bb3751ce193e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_c134a5f4-5078-4ba7-b937-a0bef090ef0a" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_35909d16-adfb-4af6-a2ba-bb3751ce193e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/DEBTConvertibleSeniorNotesdue2023NarrativeDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#DEBTConvertibleSeniorNotesdue2023NarrativeDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/DEBTConvertibleSeniorNotesdue2023NarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_e94c3ba4-80bf-4f68-be92-c4df4bd93cf1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_e94c3ba4-80bf-4f68-be92-c4df4bd93cf1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_09479478-d6f3-44c8-aec5-6bd1f5af2793" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_09479478-d6f3-44c8-aec5-6bd1f5af2793" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionOriginalDebtAmount1_d2cca75d-1b26-445b-a7b0-d70324c584e7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtConversionOriginalDebtAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtConversionOriginalDebtAmount1_d2cca75d-1b26-445b-a7b0-d70324c584e7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_1986f6e1-c06a-4889-b559-e697a1787e91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_1986f6e1-c06a-4889-b559-e697a1787e91" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfConvertibleDebt_235cde3f-1442-48ce-b108-3658ace6d0a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RepaymentsOfConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_RepaymentsOfConvertibleDebt_235cde3f-1442-48ce-b108-3658ace6d0a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_648238a5-e0d1-42cd-8499-bf9c381af89e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_648238a5-e0d1-42cd-8499-bf9c381af89e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_c096913e-f9d0-4a29-94d8-dbd0aa07bf87" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_c096913e-f9d0-4a29-94d8-dbd0aa07bf87" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_2c26f6a4-013a-48fe-b5e4-9557b8030d70" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_LongTermDebt_2c26f6a4-013a-48fe-b5e4-9557b8030d70" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_bcdaa492-2757-48da-85f6-fc5145805ed1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_7f519195-1c18-442b-aaf0-43b5c408fc7f" xlink:to="loc_us-gaap_DebtInstrumentTable_bcdaa492-2757-48da-85f6-fc5145805ed1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_60ec4ebd-583a-4d6f-932d-536a76ebe59a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_bcdaa492-2757-48da-85f6-fc5145805ed1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_60ec4ebd-583a-4d6f-932d-536a76ebe59a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_60ec4ebd-583a-4d6f-932d-536a76ebe59a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_60ec4ebd-583a-4d6f-932d-536a76ebe59a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_60ec4ebd-583a-4d6f-932d-536a76ebe59a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3a8f1962-d5a6-45b2-9432-a6c8d7bccf0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_60ec4ebd-583a-4d6f-932d-536a76ebe59a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3a8f1962-d5a6-45b2-9432-a6c8d7bccf0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_4c96989b-0ec1-4ed2-925b-d9a6c21e137f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3a8f1962-d5a6-45b2-9432-a6c8d7bccf0b" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_4c96989b-0ec1-4ed2-925b-d9a6c21e137f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_75a1193f-484a-46b6-9a6c-512b93dfa1db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_bcdaa492-2757-48da-85f6-fc5145805ed1" xlink:to="loc_us-gaap_DebtInstrumentAxis_75a1193f-484a-46b6-9a6c-512b93dfa1db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_75a1193f-484a-46b6-9a6c-512b93dfa1db_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_75a1193f-484a-46b6-9a6c-512b93dfa1db" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_75a1193f-484a-46b6-9a6c-512b93dfa1db_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_bb8e7b42-c34c-4e1b-a921-c3fc9eac8b35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_75a1193f-484a-46b6-9a6c-512b93dfa1db" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_bb8e7b42-c34c-4e1b-a921-c3fc9eac8b35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2023Member_773097b1-8452-42b4-b5f5-0dfb100c098d" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bb8e7b42-c34c-4e1b-a921-c3fc9eac8b35" xlink:to="loc_enph_ConvertibleSeniorNotesDue2023Member_773097b1-8452-42b4-b5f5-0dfb100c098d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockbasedCompensationExpenseDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#STOCKBASEDCOMPENSATIONSummaryofStockbasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockbasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_f189409e-11e7-43a0-a7f5-255430df0bef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_77a5059c-255a-4fe0-9bc7-8180a7957f35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_f189409e-11e7-43a0-a7f5-255430df0bef" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_77a5059c-255a-4fe0-9bc7-8180a7957f35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_6a2544fd-d502-47b8-85af-ffc468b34712" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_f189409e-11e7-43a0-a7f5-255430df0bef" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_6a2544fd-d502-47b8-85af-ffc468b34712" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_81349c44-6a67-491b-9a11-92e9adbaa7e0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_6a2544fd-d502-47b8-85af-ffc468b34712" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_81349c44-6a67-491b-9a11-92e9adbaa7e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_81349c44-6a67-491b-9a11-92e9adbaa7e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_81349c44-6a67-491b-9a11-92e9adbaa7e0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_81349c44-6a67-491b-9a11-92e9adbaa7e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_81349c44-6a67-491b-9a11-92e9adbaa7e0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_2ac24a24-fe27-4b2b-8880-96cf34cc8a9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:to="loc_us-gaap_CostOfSalesMember_2ac24a24-fe27-4b2b-8880-96cf34cc8a9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_5e2a96f3-6008-4f02-b3a0-0c2fcab8e544" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_5e2a96f3-6008-4f02-b3a0-0c2fcab8e544" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_6020124f-83d6-4635-b991-6e98fdf77a13" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingAndMarketingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_6020124f-83d6-4635-b991-6e98fdf77a13" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_f80832a8-be2b-45fb-a35b-83f61a87e6bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_f0373551-1c20-4572-8469-499016b682bf" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_f80832a8-be2b-45fb-a35b-83f61a87e6bb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a5d69076-3c76-4b51-bdce-280e4d752085" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_6a2544fd-d502-47b8-85af-ffc468b34712" xlink:to="loc_us-gaap_AwardTypeAxis_a5d69076-3c76-4b51-bdce-280e4d752085" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a5d69076-3c76-4b51-bdce-280e4d752085_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a5d69076-3c76-4b51-bdce-280e4d752085" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a5d69076-3c76-4b51-bdce-280e4d752085_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_05846372-2951-46dc-b2c5-a59b1cf44b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a5d69076-3c76-4b51-bdce-280e4d752085" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_05846372-2951-46dc-b2c5-a59b1cf44b1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_cbf8ed56-eccc-4143-a418-95d417099ca4" xlink:href="enph-20230930.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_05846372-2951-46dc-b2c5-a59b1cf44b1f" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_cbf8ed56-eccc-4143-a418-95d417099ca4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_eefee4f3-9fd3-4707-a705-39fc7fb889c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_05846372-2951-46dc-b2c5-a59b1cf44b1f" xlink:to="loc_us-gaap_EmployeeStockMember_eefee4f3-9fd3-4707-a705-39fc7fb889c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_446cfd52-ddf8-4d0c-999c-eff8c36c3c6f" xlink:href="enph-20230930.xsd#enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_05846372-2951-46dc-b2c5-a59b1cf44b1f" xlink:to="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_446cfd52-ddf8-4d0c-999c-eff8c36c3c6f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockBasedCompensationExpenseAssociatedwithEachTypeofAwardDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#STOCKBASEDCOMPENSATIONSummaryofStockBasedCompensationExpenseAssociatedwithEachTypeofAwardDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockBasedCompensationExpenseAssociatedwithEachTypeofAwardDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_029322aa-452e-4226-b46e-bd0b22a880ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_12d1ffb7-bc50-4473-9992-4e2cbf0d1d94" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_029322aa-452e-4226-b46e-bd0b22a880ff" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_12d1ffb7-bc50-4473-9992-4e2cbf0d1d94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cf578b57-550b-4e73-9936-d33a092b4097" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_029322aa-452e-4226-b46e-bd0b22a880ff" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cf578b57-550b-4e73-9936-d33a092b4097" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a4fb2528-9da7-42c7-8091-29982f120dbb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cf578b57-550b-4e73-9936-d33a092b4097" xlink:to="loc_us-gaap_AwardTypeAxis_a4fb2528-9da7-42c7-8091-29982f120dbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a4fb2528-9da7-42c7-8091-29982f120dbb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a4fb2528-9da7-42c7-8091-29982f120dbb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a4fb2528-9da7-42c7-8091-29982f120dbb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_baac155c-964c-4acc-ab31-edf3e2d8eff7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a4fb2528-9da7-42c7-8091-29982f120dbb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_baac155c-964c-4acc-ab31-edf3e2d8eff7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_0d7cdb4a-4b5a-46b0-b1e8-45b72024d853" xlink:href="enph-20230930.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_baac155c-964c-4acc-ab31-edf3e2d8eff7" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_0d7cdb4a-4b5a-46b0-b1e8-45b72024d853" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_3ed057a0-3d1f-41bf-8ae7-5fdce029103c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_baac155c-964c-4acc-ab31-edf3e2d8eff7" xlink:to="loc_us-gaap_EmployeeStockMember_3ed057a0-3d1f-41bf-8ae7-5fdce029103c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_b29e5335-e844-4cdc-98c5-20de9d678a3a" xlink:href="enph-20230930.xsd#enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_baac155c-964c-4acc-ab31-edf3e2d8eff7" xlink:to="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_b29e5335-e844-4cdc-98c5-20de9d678a3a" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockOptionsOutstandingDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#STOCKBASEDCOMPENSATIONSummaryofStockOptionsOutstandingDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofStockOptionsOutstandingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_17bfe179-e836-4569-8732-6e0e1975ba2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_17bfe179-e836-4569-8732-6e0e1975ba2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4795d179-0ab8-49b8-a59e-145e2e5e242c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4795d179-0ab8-49b8-a59e-145e2e5e242c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_5ed6e1f8-7182-412b-b92d-720813791b09" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_5ed6e1f8-7182-412b-b92d-720813791b09" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_10edea60-6c0c-479a-8d8a-12221e1075cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_10edea60-6c0c-479a-8d8a-12221e1075cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_e29a25ff-b1b3-428a-a95a-82c05d792545" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_e29a25ff-b1b3-428a-a95a-82c05d792545" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_97d34e67-c806-4069-b4c6-a5b48f96b958" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_97d34e67-c806-4069-b4c6-a5b48f96b958" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_668d04d0-e5ea-43af-86f5-ebc4cdd0d0ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_668d04d0-e5ea-43af-86f5-ebc4cdd0d0ff" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_b9ebbe87-269e-426e-b9bf-6bff5569d805" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_8b7f840f-a19f-4e1c-b876-c269397a55ba" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_b9ebbe87-269e-426e-b9bf-6bff5569d805" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_996b2931-35bc-43af-9ce7-aeb3e2bae276" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_b9ebbe87-269e-426e-b9bf-6bff5569d805" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_996b2931-35bc-43af-9ce7-aeb3e2bae276" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_996b2931-35bc-43af-9ce7-aeb3e2bae276_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_996b2931-35bc-43af-9ce7-aeb3e2bae276" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_996b2931-35bc-43af-9ce7-aeb3e2bae276_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_996b2931-35bc-43af-9ce7-aeb3e2bae276" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_RangeOneMember_1dfb28bc-ed1c-4849-977c-ce80cfe3bac4" xlink:href="enph-20230930.xsd#enph_RangeOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:to="loc_enph_RangeOneMember_1dfb28bc-ed1c-4849-977c-ce80cfe3bac4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_RangeTwoMember_b7cd3641-96ad-4286-99a0-b8a7f05f0672" xlink:href="enph-20230930.xsd#enph_RangeTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:to="loc_enph_RangeTwoMember_b7cd3641-96ad-4286-99a0-b8a7f05f0672" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_RangeThreeMember_0b288a8d-4036-4600-a1c6-3e59aa963705" xlink:href="enph-20230930.xsd#enph_RangeThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:to="loc_enph_RangeThreeMember_0b288a8d-4036-4600-a1c6-3e59aa963705" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_RangeFourMember_43e3a983-29c6-4498-951f-ec02977317b6" xlink:href="enph-20230930.xsd#enph_RangeFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:to="loc_enph_RangeFourMember_43e3a983-29c6-4498-951f-ec02977317b6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_RangeFiveMember_d2aa541c-541a-4587-85e7-cbdf0b7bd78f" xlink:href="enph-20230930.xsd#enph_RangeFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_c538e32a-0d85-4bd5-b772-a9aff3cdb2e2" xlink:to="loc_enph_RangeFiveMember_d2aa541c-541a-4587-85e7-cbdf0b7bd78f" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofRestrictedStockUnitActivityandPerformanceStockUnitsDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#STOCKBASEDCOMPENSATIONSummaryofRestrictedStockUnitActivityandPerformanceStockUnitsDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/STOCKBASEDCOMPENSATIONSummaryofRestrictedStockUnitActivityandPerformanceStockUnitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8037d249-719b-4718-a6d4-08fb75055765" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8037d249-719b-4718-a6d4-08fb75055765" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3f76d8ed-ea7d-4b35-9677-d7af6aa8b8bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3f76d8ed-ea7d-4b35-9677-d7af6aa8b8bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_ab3d5d46-1168-4aa9-8b69-60493a594040" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_ab3d5d46-1168-4aa9-8b69-60493a594040" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dc144f87-217a-4e10-973c-10bed82107ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d0a17737-b61c-4ae7-84d3-05afd6007576" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dc144f87-217a-4e10-973c-10bed82107ce" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5270cab5-c63a-4050-8dc7-1c209a552701" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber_eb865cdf-cc9a-4311-93b4-586c0c9ee910" xlink:href="enph-20230930.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber_eb865cdf-cc9a-4311-93b4-586c0c9ee910" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_08995c27-7403-4385-b110-371152ac4344" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_08995c27-7403-4385-b110-371152ac4344" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_9ec3a4c1-01c6-49e4-88fd-56ac9c31b412" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_9ec3a4c1-01c6-49e4-88fd-56ac9c31b412" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_a5fc68b0-f484-4d60-b943-769b8ab6304d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_a5fc68b0-f484-4d60-b943-769b8ab6304d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_91a346ed-717a-43b8-b3eb-d166be0ec7b5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_118a7bbc-603b-42f9-b106-6bfe76eb1138" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_91a346ed-717a-43b8-b3eb-d166be0ec7b5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0647b885-2500-4ff6-ad1c-5ad824ab0039" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingWeightedAverageExercisePrice_d6890da1-0b59-4b6f-8bad-babbf9d704da" xlink:href="enph-20230930.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingWeightedAverageExercisePrice_d6890da1-0b59-4b6f-8bad-babbf9d704da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_WeightedAverageRemainingContractualTerm_c905ada5-4fd1-4513-b1de-d66c968f6deb" xlink:href="enph-20230930.xsd#enph_WeightedAverageRemainingContractualTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_enph_WeightedAverageRemainingContractualTerm_c905ada5-4fd1-4513-b1de-d66c968f6deb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_7bd295dd-0a66-4a2b-a4ca-dd0183c447dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WeightedAverageRemainingContractualTerm_c905ada5-4fd1-4513-b1de-d66c968f6deb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_7bd295dd-0a66-4a2b-a4ca-dd0183c447dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExpectedToVestWeightedAverageRemainingContractualTerm_d4175130-ea54-4186-ae35-f09c204ead5a" xlink:href="enph-20230930.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExpectedToVestWeightedAverageRemainingContractualTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_WeightedAverageRemainingContractualTerm_c905ada5-4fd1-4513-b1de-d66c968f6deb" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExpectedToVestWeightedAverageRemainingContractualTerm_d4175130-ea54-4186-ae35-f09c204ead5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract_f4d054b2-ef2d-43d0-98fe-7880e554bc63" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract_f4d054b2-ef2d-43d0-98fe-7880e554bc63" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_2180884b-f78f-42f4-819e-cd39b044233c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract_f4d054b2-ef2d-43d0-98fe-7880e554bc63" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_2180884b-f78f-42f4-819e-cd39b044233c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_82eb7d29-b48f-4c10-8551-2954540a4074" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract_f4d054b2-ef2d-43d0-98fe-7880e554bc63" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_82eb7d29-b48f-4c10-8551-2954540a4074" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestIntrinsicValueValue_b1cb1701-a667-4ba2-81e6-e2b45ec8ea7b" xlink:href="enph-20230930.xsd#enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestIntrinsicValueValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract_f4d054b2-ef2d-43d0-98fe-7880e554bc63" xlink:to="loc_enph_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestIntrinsicValueValue_b1cb1701-a667-4ba2-81e6-e2b45ec8ea7b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharePrice_5cf9e727-6f6a-487a-9e33-d4949fee6959" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_us-gaap_SharePrice_5cf9e727-6f6a-487a-9e33-d4949fee6959" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ec60985b-9158-4dc3-b8bd-30078300d8b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_75077a1c-5f2e-4b05-9f92-475b768909b0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ec60985b-9158-4dc3-b8bd-30078300d8b0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_fb043fec-3d6a-4c70-978c-240bea198c5c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ec60985b-9158-4dc3-b8bd-30078300d8b0" xlink:to="loc_us-gaap_AwardTypeAxis_fb043fec-3d6a-4c70-978c-240bea198c5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fb043fec-3d6a-4c70-978c-240bea198c5c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_fb043fec-3d6a-4c70-978c-240bea198c5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fb043fec-3d6a-4c70-978c-240bea198c5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc003af6-b4d9-46ce-8d8e-58b37270b1a6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_fb043fec-3d6a-4c70-978c-240bea198c5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc003af6-b4d9-46ce-8d8e-58b37270b1a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_94258585-44ad-4073-8da3-fcdeeaf3b9f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc003af6-b4d9-46ce-8d8e-58b37270b1a6" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_94258585-44ad-4073-8da3-fcdeeaf3b9f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_fe7c70e1-3798-4950-9195-36d0419280a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc003af6-b4d9-46ce-8d8e-58b37270b1a6" xlink:to="loc_us-gaap_PerformanceSharesMember_fe7c70e1-3798-4950-9195-36d0419280a5" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/NETINCOMEPERSHAREScheduleofComputationofBasicandDilutedNetIncomePerShareDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#NETINCOMEPERSHAREScheduleofComputationofBasicandDilutedNetIncomePerShareDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/NETINCOMEPERSHAREScheduleofComputationofBasicandDilutedNetIncomePerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6b4fa84a-00d2-41e5-8ee5-28f8f0a967a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAbstract_c7518413-520c-4056-88b9-d3bb26867e30" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6b4fa84a-00d2-41e5-8ee5-28f8f0a967a2" xlink:to="loc_us-gaap_NetIncomeLossAbstract_c7518413-520c-4056-88b9-d3bb26867e30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_0d56a1d0-83c7-4d71-95dc-994df1f2b499" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_c7518413-520c-4056-88b9-d3bb26867e30" xlink:to="loc_us-gaap_NetIncomeLoss_0d56a1d0-83c7-4d71-95dc-994df1f2b499" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestOnConvertibleDebtNetOfTax_083b3aeb-2207-4d33-bcf4-cbd9e3a09ec2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestOnConvertibleDebtNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_c7518413-520c-4056-88b9-d3bb26867e30" xlink:to="loc_us-gaap_InterestOnConvertibleDebtNetOfTax_083b3aeb-2207-4d33-bcf4-cbd9e3a09ec2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToParentDiluted_bd998693-675f-409d-9855-6628c6f15392" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAttributableToParentDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_c7518413-520c-4056-88b9-d3bb26867e30" xlink:to="loc_us-gaap_NetIncomeLossAttributableToParentDiluted_bd998693-675f-409d-9855-6628c6f15392" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6b4fa84a-00d2-41e5-8ee5-28f8f0a967a2" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_70382143-cf70-4627-8f9b-925b412f6d57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_70382143-cf70-4627-8f9b-925b412f6d57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_daf3594d-9967-43b5-a159-2c1a060919c3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_daf3594d-9967-43b5-a159-2c1a060919c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_8a284e53-cff1-47ff-809f-d78f9110fb22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_8a284e53-cff1-47ff-809f-d78f9110fb22" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_72092984-eaf1-47c4-91a4-56f15e0faa85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_72092984-eaf1-47c4-91a4-56f15e0faa85" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_94c34d0a-7d56-41eb-8406-61df27680243" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c70e2ab5-2d26-4da4-b697-b2e48eefe5e2" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_94c34d0a-7d56-41eb-8406-61df27680243" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EarningsPerShareBasicAndDilutedEPSAbstract_df5b0d71-99c7-4cad-851e-0ba7c4273cd6" xlink:href="enph-20230930.xsd#enph_EarningsPerShareBasicAndDilutedEPSAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6b4fa84a-00d2-41e5-8ee5-28f8f0a967a2" xlink:to="loc_enph_EarningsPerShareBasicAndDilutedEPSAbstract_df5b0d71-99c7-4cad-851e-0ba7c4273cd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_980ef61f-fc88-4fea-bece-fdbaf7c48e25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_EarningsPerShareBasicAndDilutedEPSAbstract_df5b0d71-99c7-4cad-851e-0ba7c4273cd6" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_980ef61f-fc88-4fea-bece-fdbaf7c48e25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_4229dbc8-af36-47d1-ae3c-1ef89bb3f95c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_enph_EarningsPerShareBasicAndDilutedEPSAbstract_df5b0d71-99c7-4cad-851e-0ba7c4273cd6" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_4229dbc8-af36-47d1-ae3c-1ef89bb3f95c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7e0badbe-5837-4cac-9be8-a5fec9f6a8f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_6b4fa84a-00d2-41e5-8ee5-28f8f0a967a2" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7e0badbe-5837-4cac-9be8-a5fec9f6a8f0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_fc44b9a2-16ec-4960-80c9-1271f123d79c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7e0badbe-5837-4cac-9be8-a5fec9f6a8f0" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_fc44b9a2-16ec-4960-80c9-1271f123d79c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_fc44b9a2-16ec-4960-80c9-1271f123d79c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fc44b9a2-16ec-4960-80c9-1271f123d79c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_fc44b9a2-16ec-4960-80c9-1271f123d79c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ffeb5d2f-9ce4-42df-92db-c1a2d586eb12" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fc44b9a2-16ec-4960-80c9-1271f123d79c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ffeb5d2f-9ce4-42df-92db-c1a2d586eb12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_3363fc5e-6bae-40b2-bd86-7cff6d8ec367" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ffeb5d2f-9ce4-42df-92db-c1a2d586eb12" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_3363fc5e-6bae-40b2-bd86-7cff6d8ec367" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_0fca0067-05ec-4c2f-9723-961354177880" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7e0badbe-5837-4cac-9be8-a5fec9f6a8f0" xlink:to="loc_us-gaap_DebtInstrumentAxis_0fca0067-05ec-4c2f-9723-961354177880" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0fca0067-05ec-4c2f-9723-961354177880_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_0fca0067-05ec-4c2f-9723-961354177880" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0fca0067-05ec-4c2f-9723-961354177880_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_0fca0067-05ec-4c2f-9723-961354177880" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2023Member_a7cf2095-27b0-40cc-9eed-219792410129" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:to="loc_enph_ConvertibleSeniorNotesDue2023Member_a7cf2095-27b0-40cc-9eed-219792410129" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_1c9a5a5e-6124-4204-9bda-486243383662" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_1c9a5a5e-6124-4204-9bda-486243383662" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_c16414b2-6813-40d1-a9d5-0a7a8f7efe4c" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_c16414b2-6813-40d1-a9d5-0a7a8f7efe4c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_ef5bac8d-0edd-49e2-8852-c28580a45bde" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_491afcc3-4304-4de4-84c3-dc306d67fb65" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_ef5bac8d-0edd-49e2-8852-c28580a45bde" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/NETINCOMEPERSHAREScheduleofPotentiallyDilutiveSecuritiesExcludedfromtheComputationofDilutedNetIncomePerShareDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#NETINCOMEPERSHAREScheduleofPotentiallyDilutiveSecuritiesExcludedfromtheComputationofDilutedNetIncomePerShareDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/NETINCOMEPERSHAREScheduleofPotentiallyDilutiveSecuritiesExcludedfromtheComputationofDilutedNetIncomePerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_a9e9eac8-7a64-4fff-a87e-e22c359c76b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_0fb228d8-d0e1-4454-9094-6684fd1e665b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_a9e9eac8-7a64-4fff-a87e-e22c359c76b8" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_0fb228d8-d0e1-4454-9094-6684fd1e665b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_115ac4d8-32e9-40cb-a6a6-ce2cd97da205" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_a9e9eac8-7a64-4fff-a87e-e22c359c76b8" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_115ac4d8-32e9-40cb-a6a6-ce2cd97da205" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a4c31405-ecb8-4910-9618-834523058a70" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_115ac4d8-32e9-40cb-a6a6-ce2cd97da205" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a4c31405-ecb8-4910-9618-834523058a70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a4c31405-ecb8-4910-9618-834523058a70_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a4c31405-ecb8-4910-9618-834523058a70" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a4c31405-ecb8-4910-9618-834523058a70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c349a3ea-f7ef-4923-a82c-e39f059ffacd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a4c31405-ecb8-4910-9618-834523058a70" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c349a3ea-f7ef-4923-a82c-e39f059ffacd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_ed2e3941-64df-4e59-9c7e-abbeed669b77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c349a3ea-f7ef-4923-a82c-e39f059ffacd" xlink:to="loc_us-gaap_StockCompensationPlanMember_ed2e3941-64df-4e59-9c7e-abbeed669b77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_75e138a9-2338-42ac-85ce-0e198b4bc9c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c349a3ea-f7ef-4923-a82c-e39f059ffacd" xlink:to="loc_us-gaap_WarrantMember_75e138a9-2338-42ac-85ce-0e198b4bc9c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_d8c7c0ef-b05d-4e1f-bb30-0f682e2cc68d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c349a3ea-f7ef-4923-a82c-e39f059ffacd" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_d8c7c0ef-b05d-4e1f-bb30-0f682e2cc68d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_115ac4d8-32e9-40cb-a6a6-ce2cd97da205" xlink:to="loc_us-gaap_DebtInstrumentAxis_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6a70142d-2a90-4186-8e0a-0a573bdfdd6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_beb5eeaa-dca2-41c8-aee3-73f50d7eb0a7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6a70142d-2a90-4186-8e0a-0a573bdfdd6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2028Member_ef4c3eaa-e36e-4cf1-a828-1d788b7a1f90" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6a70142d-2a90-4186-8e0a-0a573bdfdd6f" xlink:to="loc_enph_ConvertibleSeniorNotesDue2028Member_ef4c3eaa-e36e-4cf1-a828-1d788b7a1f90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2026Member_f4414194-a373-458a-b1a4-8bb34967873a" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6a70142d-2a90-4186-8e0a-0a573bdfdd6f" xlink:to="loc_enph_ConvertibleSeniorNotesDue2026Member_f4414194-a373-458a-b1a4-8bb34967873a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2025Member_e5476a39-a70a-41e5-85fc-51ad0b36d727" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6a70142d-2a90-4186-8e0a-0a573bdfdd6f" xlink:to="loc_enph_ConvertibleSeniorNotesDue2025Member_e5476a39-a70a-41e5-85fc-51ad0b36d727" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://enphase.com/role/RELATEDPARTYDetails" xlink:type="simple" xlink:href="enph-20230930.xsd#RELATEDPARTYDetails"/>
  <link:definitionLink xlink:role="http://enphase.com/role/RELATEDPARTYDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_5ebf14fa-4d85-4f46-9ae6-c33ade681d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_94aed35f-afab-4e91-894a-b1fb5ba635b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_5ebf14fa-4d85-4f46-9ae6-c33ade681d3a" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_94aed35f-afab-4e91-894a-b1fb5ba635b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae255575-4422-4427-b410-694617182f82" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_5ebf14fa-4d85-4f46-9ae6-c33ade681d3a" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae255575-4422-4427-b410-694617182f82" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae255575-4422-4427-b410-694617182f82" xlink:to="loc_srt_CounterpartyNameAxis_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b6ce777b-809d-493f-b4cc-7307f791b324" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_cdca9e7c-850e-40a4-a9b3-28d39d6bd9f9" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b6ce777b-809d-493f-b4cc-7307f791b324" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ThurmanJohnRodgersMember_4948f94f-2c4a-4f2e-9a7f-38ffe0b21101" xlink:href="enph-20230930.xsd#enph_ThurmanJohnRodgersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b6ce777b-809d-493f-b4cc-7307f791b324" xlink:to="loc_enph_ThurmanJohnRodgersMember_4948f94f-2c4a-4f2e-9a7f-38ffe0b21101" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_00a08a3c-2131-42bc-aaa8-7202cb803eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae255575-4422-4427-b410-694617182f82" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_00a08a3c-2131-42bc-aaa8-7202cb803eb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_00a08a3c-2131-42bc-aaa8-7202cb803eb4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_00a08a3c-2131-42bc-aaa8-7202cb803eb4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_00a08a3c-2131-42bc-aaa8-7202cb803eb4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6e03cc82-c273-4aa4-b1d0-6d43f4d9d503" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_00a08a3c-2131-42bc-aaa8-7202cb803eb4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6e03cc82-c273-4aa4-b1d0-6d43f4d9d503" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_549340ee-434c-459e-b6f0-663edf40ec14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6e03cc82-c273-4aa4-b1d0-6d43f4d9d503" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_549340ee-434c-459e-b6f0-663edf40ec14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_96b78334-892d-4fd7-8cfc-cd2a7ef202f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae255575-4422-4427-b410-694617182f82" xlink:to="loc_us-gaap_DebtInstrumentAxis_96b78334-892d-4fd7-8cfc-cd2a7ef202f0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_96b78334-892d-4fd7-8cfc-cd2a7ef202f0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_96b78334-892d-4fd7-8cfc-cd2a7ef202f0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_96b78334-892d-4fd7-8cfc-cd2a7ef202f0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7a34b420-63d0-4eeb-8163-7a66eb33086f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_96b78334-892d-4fd7-8cfc-cd2a7ef202f0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7a34b420-63d0-4eeb-8163-7a66eb33086f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_ConvertibleSeniorNotesDue2023Member_bcd814b9-14d7-499c-ab04-c1ab6fa798b8" xlink:href="enph-20230930.xsd#enph_ConvertibleSeniorNotesDue2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7a34b420-63d0-4eeb-8163-7a66eb33086f" xlink:to="loc_enph_ConvertibleSeniorNotesDue2023Member_bcd814b9-14d7-499c-ab04-c1ab6fa798b8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate202006Member" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate202006Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember" xlink:to="loc_us-gaap_AccountingStandardsUpdate202006Member" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_4e84700a-f278-4488-8703-d54f5046f1ff" xlink:href="enph-20230930.xsd#enph_EmployeeStockOptionsAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_enph_EmployeeStockOptionsAndRestrictedStockUnitsMember_4e84700a-f278-4488-8703-d54f5046f1ff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_EmployeeStockMember" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_89354083-2267-4d2e-81db-d49eed5139d6" xlink:href="enph-20230930.xsd#enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_enph_PostCombinationExpenseAccrualAccruedLiabilitiesMember_89354083-2267-4d2e-81db-d49eed5139d6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_PerformanceSharesMember" xlink:type="arc" order="8"/>
  </link:definitionLink>
</link:linkbase>
