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                                                                     EXHIBIT 5.1


                                October 8, 2003

Big 5 Sporting Goods Corporation
2525 E. El Segundo Blvd.
El Segundo, CA 90245

      Re:   Registration of 6,171,074 shares of common stock, $0.01 par value
            per share, of Big 5 Sporting Goods Corporation, pursuant to a
            Registration Statement on Form S-3

Ladies and Gentlemen:

         In connection with the registration for resale of 6,171,074 shares of
common stock, $0.01 par value per share (the "Shares"), of Big 5 Sporting Goods
Corporation, a Delaware corporation (the "Company"), under the Securities Act of
1933, as amended, on Form S-3 (the "Registration Statement"), you have requested
our opinion with respect to the matters set forth below. The Shares were issued
to Green Equity Investors, L.P. on September 25, 1992 and/or on June 26, 2002.

         We have made such legal and factual examinations and inquiries,
including an examination of originals or copies certified or otherwise
identified to our satisfaction of such documents, corporate records and
instruments, as we have deemed necessary or appropriate for purposes of this
opinion.

         In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
copies.

         We are opining herein as to the effect on the subject transaction only
of the General Corporation Law of the State of Delaware, and we express no
opinion with respect to the applicability thereto, or the effect thereon, of the
laws of any other jurisdiction or, in the case of Delaware, any other laws.

         Subject to the foregoing, it is our opinion that the Shares are validly
issued, fully paid and non-assessable.

         This opinion is rendered only to the Company and is solely for the
benefit of the Company in connection with the transaction covered hereby. This
opinion may not be relied upon by you for any other purpose, or furnished to,
quoted to or relied upon by any other person, firm or corporation for any
purpose, without our prior written consent.


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Big 5 Sporting Goods Corporation
October 8, 2003
Page 2


         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained under the
heading "Legal Matters."

                                                     Very truly yours,

                                                     /s/ Irell & Manella LLP

                                                     IRELL & MANELLA LLP

