<SUBMISSION>
<ACCESSION-NUMBER>0000706688-20-000114
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20200731
<FILING-DATE>20200804
<DATE-OF-FILING-DATE-CHANGE>20200804
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Wall Christopher K
<CIK>0001820194
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-13941
<FILM-NUMBER>201075134
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>400 GALLERIA PARKWAY SE
<STREET2>SUITE 300
<CITY>ATLANTA
<STATE>GA
<ZIP>30339
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>AARON'S INC
<CIK>0000706688
<ASSIGNED-SIC>7359
<IRS-NUMBER>580687630
<STATE-OF-INCORPORATION>GA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>400 GALLERIA PARKWAY SE
<STREET2>SUITE 300
<CITY>ATLANTA
<STATE>GA
<ZIP>30339
<PHONE>678-402-3000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>400 GALLERIA PARKWAY SE
<STREET2>SUITE 300
<CITY>ATLANTA
<STATE>GA
<ZIP>30339
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>AARON RENTS INC
<DATE-CHANGED>19920703
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_159658518512835.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-07-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000706688</issuerCik>
        <issuerName>AARON'S INC</issuerName>
        <issuerTradingSymbol>AAN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001820194</rptOwnerCik>
            <rptOwnerName>Wall Christopher K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>400 GALLERIA PKWY SE, SUITE 300</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ATLANTA</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30339</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Interim CFO, Aaron's, Inc.</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2454</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>52.18</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7803</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock award which is expected to vest in three equal increments on each of March 7, 2021, 2022 and 2023, subject to the grant agreement between the Issuer and the Reporting Person.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Robert P. Sinclair, by Power of Attorney for Christopher K. Wall</signatureName>
        <signatureDate>2020-08-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
