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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-08-30</periodOfReport>

    <issuer>
        <issuerCik>0000037472</issuerCik>
        <issuerName>FLEXSTEEL INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>FLXS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194570</rptOwnerCik>
            <rptOwnerName>DITTMER JERALD K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 877</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DUBUQUE</rptOwnerCity>
            <rptOwnerState>IA</rptOwnerState>
            <rptOwnerZipCode>52004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>President &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-08-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>22165</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33671</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option 08/30/2019</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.14</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2019-08-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2029-08-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Option 12/28/2018</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.96</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2028-12-28</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>85000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>45710</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45710</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On 12/28/2018, 3,186 shares of restricted stock were granted. The restricted stock award vests in four installments. On July 1, 2019, 531 shares vested, on July 1, 2020, 1,062 shares shall vest, on July 1, 2021, 1,062 shares shall vest, and on July 1, 2022, 531 shares shall vest. Vested shares will be delivered to the reporting person on July 1 of each respective year.</footnote>
        <footnote id="F2">On 08/30/2019, 22,165 shares of restricted stock were granted. The restricted stock award vests on September 11, 2019.</footnote>
        <footnote id="F3">On 12/28/18, 85,000 options were granted. The options vest in three installments. On July 1, 2019, 28,334 options vested, on July 1, 2020, 28,333 options shall vest, and on July 1, 2021, 28,333 options shall vest.</footnote>
        <footnote id="F4">Each restricted stock unit represents a contingent right to receive one share of FLXS common stock.</footnote>
        <footnote id="F5">On 12/28/2018, 30,000 restricted stock units were granted. These restricted stock units vest in four installments. On July 1, 2019, 5,000 shares shall vest, on July 1, 2020, 10,000 shares shall vest, on July 1, 2021, 10,000 shares shall vest, and on July 1, 2022, 5,000 shares shall vest. Vested shares will be delivered to the reporting person on July 1 of each respective year.</footnote>
        <footnote id="F6">On 07/19/2019, 20,710 restricted stock units were granted. These restricted stock units vest on June 30, 2022.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Rebecca J. Kuhle, attorney-in-fact</signatureName>
        <signatureDate>2019-09-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
