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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000731012</issuerCik>
        <issuerName>HEALTHCARE SERVICES GROUP INC</issuerName>
        <issuerTradingSymbol>HCSG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000946426</rptOwnerCik>
            <rptOwnerName>FROME ROBERT L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3220 TILLMAN DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>BENSALEM</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19020</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>1</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>216</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.62</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26817</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person has elected to receive fully vested shares of Deferred Stock Units (&quot;DSUs&quot;) under the Issuer's 2020 Amended Omnibus Incentive Plan in lieu of cash fees payable for service on the Issuer's Board of Directors and any committees thereof. The reporting person made this election in November 2023 which applies to the director's fees earned in 2024 in compliance with the Issuer's black-out period guidelines. The number of shares represents the quotient of the amount of such fees divided by the Issuer's closing stock price on the date such fees would otherwise be paid, rounded up to the nearest whole share. Such DSUs will be settled in shares of common stock ninety days following separation of service from the Board. The reporting person may elect a further deferral beyond the Settlement Date pursuant to the rules of Code Section 409 A.</footnote>
        <footnote id="F2">Amount represents 3,728 unvested DSUs, 8,181 vested DSUs, and 14,908 shares of common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Michael Harrity, by Power of Attorney</signatureName>
        <signatureDate>2025-01-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
