<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-06-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001132105</issuerCik>
        <issuerName>SPORTSMAN'S WAREHOUSE HOLDINGS, INC.</issuerName>
        <issuerTradingSymbol>SPWH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001414321</rptOwnerCik>
            <rptOwnerName>Schaefer John V.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SPORTSMAN'S WAREHOUSE</rptOwnerStreet1>
            <rptOwnerStreet2>7035 HIGH TECH DRIVE</rptOwnerStreet2>
            <rptOwnerCity>MIDVALE</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84047</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>66563</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.301</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>243404.984</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.215 to $5.48, inclusive. The reporting person undertakes to provide to Sportsman's Warehouse Holdings, Inc. (the &quot;Issuer&quot;) and any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) to this Form 4.</footnote>
        <footnote id="F3">Includes 91,467 shares of restricted stock, which are scheduled to vest in substantially equal installments on April 16, 2018 and April 16, 2019 subject to the Reporting Person's continued employment.</footnote>
        <footnote id="F4">Includes 150,000 restricted stock units which are scheduled to vest, subject to the Reporting Person's continued employment, as to one-third of the shares awarded on April 16, 2018, April 16, 2019, and April 16, 2020. Each restricted stock unit represents the right to receive one share of the Issuer's common stock</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>John V. Shaefer</signatureName>
        <signatureDate>2017-07-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
