<SEC-DOCUMENT>0001469367-21-000095.txt : 20210409
<SEC-HEADER>0001469367-21-000095.hdr.sgml : 20210409
<ACCEPTANCE-DATETIME>20210409202224
ACCESSION NUMBER:		0001469367-21-000095
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201021
FILED AS OF DATE:		20210409
DATE AS OF CHANGE:		20210409

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bywater David
		CENTRAL INDEX KEY:			0001673823

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37511
		FILM NUMBER:		21819141

	MAIL ADDRESS:	
		STREET 1:		1850 WEST ASHTON BLVD
		CITY:			LEHI
		STATE:			UT
		ZIP:			84043

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Sunrun Inc.
		CENTRAL INDEX KEY:			0001469367
		STANDARD INDUSTRIAL CLASSIFICATION:	HEATING EQUIP, EXCEPT ELEC & WARM AIR & PLUMBING FIXTURES [3430]
		IRS NUMBER:				262841711
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		225 BUSH STREET, SUITE 1400
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		415-580-6900

	MAIL ADDRESS:	
		STREET 1:		225 BUSH STREET, SUITE 1400
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SunRun Inc.
		DATE OF NAME CHANGE:	20090730
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>wf-form4a_161801413069393.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2020-10-21</periodOfReport>

    <dateOfOriginalSubmission>2020-10-23</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001469367</issuerCik>
        <issuerName>Sunrun Inc.</issuerName>
        <issuerTradingSymbol>RUN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001673823</rptOwnerCik>
            <rptOwnerName>Bywater David</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUNRUN INC.</rptOwnerStreet1>
            <rptOwnerStreet2>225 BUSH STREET, SUITE 1400</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO of Vivint Solar, Inc.</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>56.82</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-10-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>33991</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2021-10-08</value>
            </exerciseDate>
            <expirationDate>
                <value>2030-10-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>33991.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33991</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>56.82</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-10-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>42867</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2021-04-08</value>
            </exerciseDate>
            <expirationDate>
                <value>2030-10-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>42867.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42867</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jay Maloney, Attorney-in-Fact</signatureName>
        <signatureDate>2021-04-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
