<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-06-26</periodOfReport>
    <issuer>
        <issuerCik>0001163428</issuerCik>
        <issuerName>WILLOW GROVE BANCORP INC/NEW</issuerName>
        <issuerTradingSymbol>WGBC</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001213477</rptOwnerCik>
            <rptOwnerName>RAMSEY SAMUEL H III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-06-26</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8208</value></transactionShares><transactionValue><value>3.97</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>66195</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value><footnoteId id="F2"/></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Stock Option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>3.97</value></conversionOrExercisePrice><transactionDate><value>2003-06-26</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8208</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2000-10-26</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2009-10-26</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>8208</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>10033</value><footnoteId id="F4"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Includes 16,916 shares held in the 1999 and 2002 Recognition and Retention Plan Trusts allocated to the Reporting Person that vest in five equal annual installments beginning on the first anniversary of the date of grant.</footnote><footnote id="F2">The reporting person also indirectly beneficially owns 19,173 shares of the issuer's common stock in a trust for which he is a beneficiary.</footnote><footnote id="F3">The options vest in five equal annual installments beginning on October 26, 2000.</footnote><footnote id="F4">The reporting person also directly beneficially owns 32,070 and 4,266 stock options that have an exercise price of $12.79 and $8.33, respectively, and vest in five equal annual installments beginning on November 25, 2003 and January 22, 2003, respectively.</footnote></footnotes><ownerSignature><signatureName>Samuel H. Ramsey, III</signatureName><signatureDate>2003-06-30</signatureDate></ownerSignature></ownershipDocument>

