<PAGE>   1
                                                                    EXHIBIT 10.2


[THQ LETTERHEAD]

                                 June 12, 2001

Union Bank of California, N.A.,
   as Agent and a Lender
445 South Figueroa Street
Los Angeles, California 90071
Attention: Ann Forbes

BNP Paribas
180 Montgomery Street
San Francisco, California 94104
Attention: Inga Buschbaum

Pacific Century Bank, N.A.
16030 Ventura Boulevard
Encino, California 91436
Attention: Jill Schuberth

      Re:   Third Amendment to Revolving Credit Agreement

Ladies and Gentlemen:

      We refer to the Revolving Credit Agreement date as of August 31, 2000, as
amended by the First Amendment to Revolving Credit Agreement dated October 23,
2000 and the Second Amendment to Revolving Credit Agreement dated February 20,
2001 (said Agreement, as so amended, herein called the "Credit Agreement"),
among THQ Inc. (the "Borrower"), each of Union Bank of California, N.A., BNP
Paribas and Pacific Century Bank, N.A. (the "Lenders") and Union Bank of
California, N.A., as administrative agent (in such capacity, the "Agent") for
the Lenders, as syndication agent and as arranger. Terms defined in the Credit
Agreement and not otherwise defined herein have the same respective meanings
when used herein, and the rules of interpretation set forth in Sections 1.2 and
1.3 of the Credit Agreement are incorporated by reference herein.

      1.    Effective as of the date of this letter amendment but subject to
the terms and conditions hereof, the Borrower and the Lenders hereby agree that
the definition of "Commitment Termination Date" in Section 1.1 of the Credit
Agreement is amended in full to read as follows:

              "`Commitment Termination Date' means July 31, 2001."
<PAGE>   2
Union Bank of California, N.A.
BNP Paribas
Pacific Century Bank, N.A.
June 12, 2001
Page 2


     2.   The Borrower hereby represents and warrants for the benefit of the
Lenders and the Agent that (a) the representations and warranties contained in
the Credit Documents are correct in all material respects on and as of the date
of this letter amendment, before and after giving effect to the same, as if
made on and as of such date, and (b) no event has occurred and is continuing,
or would result from the effectiveness of this letter amendment, that
constitutes a Default.

     3.   This letter amendment shall become effective when the Agent has
received all of the following documents, in form and substance satisfactory to
the Agent and in the number of originals requested thereby: (a) this letter
amendment, duly executed by the Borrower and the Lenders; (b) a consent to this
letter amendment, duly executed by THQ/Jakks; and (c) such other approvals,
opinions, evidence and documents as any Lender may reasonably request.

     4.   On and after the effective date of this letter amendment, each
reference in the Credit Agreement to "this Agreement," "hereunder," "hereof,"
"herein" or words of like import referring to the Credit Agreement, and each
reference in the other Credit Documents to "the Credit Agreement," "thereunder,"
"thereof," "therein" or words of like import referring to the Credit Agreement,
shall mean and be a reference to the Credit Agreement as amended by this letter
amendment. The Credit Agreement, as amended by this letter amendment, is and
shall continue to be in full force and effect and is hereby ratified and
confirmed in all respects. The execution, delivery and effectiveness of this
letter amendment shall not operate as a waiver of any right, power or remedy of
the Agent or any Lender under any of the Credit Documents or constitute a waiver
of any provision of any of the Credit Documents.

     5.   This letter amendment may be executed in any number of counterparts
and by any combination of the parties hereto in separate counterparts, each of
which counterparts shall be an original and all of which taken together shall
constitute one and the same letter amendment.

<PAGE>   3
Union Bank of California, N.A.
BNP Paribas
Pacific Century Bank, N.A.
June 12, 2001
Page 3


     6. THIS LETTER AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF CALIFORNIA WITHOUT REFERENCE TO
THE CHOICE-OF-LAW PRINCIPLES THEREOF.


                                        Very truly yours

                                        THQ INC.

                                        By: /s/ FRED GYSI
                                            --------------------------
                                            Fred Gysi
                                            Senior Vice President,
                                             Finance & Administration
                                             & Chief Financial Officer


Agreed as of the date first written above:


UNION BANK OF CALIFORNIA, N.A.
 as Agent and Lender


By:
   ------------------------------
Name:
     ----------------------------
Title:
      ---------------------------
<PAGE>   4
Union Bank of California, N.A.
BNP Paribas
Pacific Century Bank, N.A.
June 12, 2001
Page 3


     6. THIS LETTER AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF CALIFORNIA WITHOUT REFERENCE TO
THE CHOICE-OF-LAW PRINCIPLES THEREOF.


                                        Very truly yours

                                        THQ INC.

                                        By:
                                            --------------------------
                                            Fred Gysi
                                            Senior Vice President,
                                             Finance & Administration
                                             & Chief Financial Officer


Agreed as of the date first written above:


UNION BANK OF CALIFORNIA, N.A.
 as Agent and Lender


By:  /s/ ANN FORBES
   ------------------------------
Name:  Ann Forbes
     ----------------------------
Title:  V.P.
      ---------------------------
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Union Bank of California, N.A.
BNP Paribas
Pacific Century Bank, N.A.
June 12, 2001
Page 4


BNP PARIBAS


By: /s/ PETER LUPO
   --------------------------
Name: Peter Lupo
     ------------------------
Title: Vice President
      -----------------------


By: /s/ GERRY ARTEAGE
   --------------------------
Name: Gerry Arteage
     ------------------------
Title: Vice President
      -----------------------


PACIFIC CENTURY BANK, N.A.

By:
   --------------------------
Name:
     ------------------------
Title:
      -----------------------
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Union Bank of California, N.A.
BNP Paribas
Pacific Century Bank, N.A.
June 12, 2001
Page 4


BNP PARIBAS


By:
   --------------------------
Name:
     ------------------------
Title:
      -----------------------


By:
   --------------------------
Name:
     ------------------------
Title:
      -----------------------


PACIFIC CENTURY BANK, N.A.

By: /s/ JILL S. SCHUBERTH
   --------------------------
Name: Jill S. Schuberth
     ------------------------
Title:  Vice President
      -----------------------