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

    <documentType>4</documentType><periodOfReport>2003-10-22</periodOfReport>
    <issuer>
        <issuerCik>0000874691</issuerCik>
        <issuerName>OUTBACK STEAKHOUSE INC</issuerName>
        <issuerTradingSymbol>OSI</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001044540</rptOwnerCik>
            <rptOwnerName>FIELDS DEBBI</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OUTBACK STEAKHOUSE, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2202 N. WEST SHORE BLVD., 5TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>TAMPA</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33607</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Phantom Stock Units (&quot;PSU&quot;)</value></securityTitle><conversionOrExercisePrice><footnoteId id="F1"/></conversionOrExercisePrice><transactionDate><value>2003-10-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>122.93</value></transactionShares><transactionPricePerShare><value>38.64</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>122.93</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4248.1</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">The security converts to common stock on a one-to-one basis.</footnote><footnote id="F2">The PSU were accrued under the Company's Deferred Compensation and Stock Plan (&quot;Plan&quot;) and are settled 100% in the Company's common stock upon cessation as a director.</footnote><footnote id="F3">Derivative securities beneficially owned at end of year include: (i) 448.97 PSU accrued in 1997 at prices ranging from $15.840 to $17.669; (ii) 439.26 PSU accrued in 1998 at prices ranging from $18.070 to $24.697; (iii) 672.73 PSU accrued in 1999 at prices ranging from $25.33 to $36.68; (iv) 756.99 PSU acquired in 2000 at prices ranging from $23.603 to $29.821; (v) 688.46 PSU acquired in 2001 at prices ranging from $24.85 to $27.98; (vi) 646.71 PSU acquired in 2002 at prices ranging from $28.00 to $37.38; and (vii) 472.04 PSU acquired in 2003 at prices ranging from $33.82 to $38.64, all such PSU are to be settled 100% in the Company's common stock upon cessation as a director.</footnote></footnotes><remarks/><ownerSignature><signatureName>Joseph J. Kadow, Attorney-in-Fact</signatureName><signatureDate>2003-10-22</signatureDate></ownerSignature></ownershipDocument>

