<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-08-12</periodOfReport>
    <issuer>
        <issuerCik>0000057131</issuerCik>
        <issuerName>LA-Z-BOY INC</issuerName>
        <issuerTradingSymbol>LZB</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001246405</rptOwnerCik>
            <rptOwnerName>HEHL DAVID K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1284 N. TELEGRAPH ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MONROE</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48162</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Shares</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5616</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Spouse</value></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Shares</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>21756</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to buy)</value></securityTitle><conversionOrExercisePrice><value>5.11</value></conversionOrExercisePrice><transactionDate><value>2003-08-12</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionAmounts><transactionShares><value>1400</value></transactionShares><transactionPricePerShare><value>5.11</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-08-12</value></exerciseDate><expirationDate><value>2003-09-12</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value></underlyingSecurityTitle><underlyingSecurityShares><value>1400</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1400</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">These were granted under the Restricted Share Plan for Non-Employee Directors as amended and restated through August 12, 2003.</footnote><footnote id="F2">The reporting person disclaims beneficial ownership of these securities, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 or for any other purpose.</footnote></footnotes><remarks/><ownerSignature><signatureName>James P. Klarr, Attorney-in-fact</signatureName><signatureDate>2003-08-13</signatureDate></ownerSignature></ownershipDocument>

