<SEC-DOCUMENT>0001628280-25-006539.txt : 20250219
<SEC-HEADER>0001628280-25-006539.hdr.sgml : 20250219
<ACCEPTANCE-DATETIME>20250219215448
ACCESSION NUMBER:		0001628280-25-006539
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250218
FILED AS OF DATE:		20250219
DATE AS OF CHANGE:		20250219

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Dickens Zachary T
		CENTRAL INDEX KEY:			0001799962
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32269
		FILM NUMBER:		25643067

	MAIL ADDRESS:	
		STREET 1:		2795 E COTTONWOOD PARKWAY
		STREET 2:		SUITE 300
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84121

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Extra Space Storage Inc.
		CENTRAL INDEX KEY:			0001289490
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		ORGANIZATION NAME:           	05 Real Estate & Construction
		IRS NUMBER:				201076777
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2795 COTTONWOOD PARKWAY, SUITE 400
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84121
		BUSINESS PHONE:		801-562-5556

	MAIL ADDRESS:	
		STREET 1:		2795 COTTONWOOD PARKWAY, SUITE 400
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84121
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1740020082.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-02-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001289490</issuerCik>
        <issuerName>Extra Space Storage Inc.</issuerName>
        <issuerTradingSymbol>EXR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001799962</rptOwnerCik>
            <rptOwnerName>Dickens Zachary T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2795 EAST COTTONWOOD PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>SALT LAKE CITY</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Chief Investment Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-02-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>91</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>154.92</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19135</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>80</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Roth IRA</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares withheld by the Issuer in payment of the tax liability arising in connection with the settlement of vested restricted stock awards. Restricted stock awards vest 25% annually over four years, beginning on the first anniversary of the grant date.</footnote>
        <footnote id="F2">The information in this report is based on plan information as of February 14, 2024.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Grace Kunde, Attorney-in-Fact</signatureName>
        <signatureDate>2025-02-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
