Exhibit 5.1

                                 BRYAN CAVE LLP
                           1290 AVENUE OF THE AMERICAS
                            NEW YORK, NEW YORK 10104
                                 (212) 541-2000

                            FACSIMILE: (212) 541-4630

                                November 19, 2002

Activision, Inc.
3100 Ocean Park Blvd.
Santa Monica, CA 90405

     Re:  Activision, Inc.
          Registration Statement on Form S-3

Ladies and Gentlemen:

     We have acted as counsel to Activision, Inc. (the "Company") in connection
with the Registration Statement on Form S-3 (the "Registration Statement") to be
filed by the Company on or about the date hereof with the Securities and
Exchange Commission (the "Commission") under the Securities Act of 1933, as
amended (the "Act"), relating to (i) unsecured debt securities ("Debt
Securities"), which may be either senior or subordinated Debt Securities, (ii)
shares of preferred stock, par value $.000001 per share ("Preferred Stock"),
(iii) shares of common stock, par value $.000001 per share ("Common Stock"),
(iv) warrants to purchase Securities (as hereinafter defined) of the Company
(collectively, "Warrants"), (v) rights to purchase Preferred Stock and Common
Stock ("Rights"), (vi) purchase contracts obligating holders to purchase
Securities (as hereinafter defined) at a future date or dates ("Purchase
Contracts") and (vii) units comprised of one or more Securities (as hereinafter
defined) in any combination ("Units," and together with the Debt Securities,
Preferred Stock, Common Stock, Warrants, Rights and Purchase Contracts, the
"Securities"), to be offered by the Company from time to time pursuant to Rule
415 under the Act for an aggregate initial offering price not to exceed
$500,000,000. Capitalized terms used and not otherwise defined herein have the
respective meanings ascribed to such terms in the Registration Statement.

     In rendering the opinions expressed below, we have examined the Amended and
Restated Certificate of Incorporation, as amended (the "Charter") and the
Amended and Restated Bylaws of the Company, each as amended to date (together,
the "Charter Documents"), and originals or conformed copies of such corporate
records, agreements and instruments of the Company, certificates of public
officials and officers of the Company, and such other documents and records, and
such matters of law, as we have deemed appropriate as a basis for the opinions
hereinafter expressed. In our examination, we have assumed the genuineness of
all signatures, the legal capacity of natural persons, the authenticity of
documents submitted to us as originals and the conformity with authentic
original documents of all documents submitted to us as copies. When relevant
facts were not independently established, we have relied upon statements of
governmental officials and upon representations made in or pursuant to the
Registration Statement and certificates and statements of appropriate
representatives of the Company, and with respect to good standing and related
matters, we have relied solely upon a certificate of the Secretary of State of
Delaware.

     In rendering the opinions expressed below, we have assumed that (i) the
Registration Statement, and any amendments thereto (including post-effective
amendments) will have become effective; (ii) a prospectus supplement will have
been prepared and filed with the Commission describing the Securities offered
thereby; (iii) all Securities will be issued and sold in compliance with
applicable federal and state securities laws and in the manner described in the
Registration Statement and the appropriate prospectus supplement; (iv) a
definitive purchase, underwriting or similar agreement with respect to any
Securities offered will have been duly authorized and validly executed and
delivered by the Company and the other parties thereto; (v) any securities
issuable upon conversion, exchange, redemption or exercise of any Securities
being offered will have been duly authorized, created and, if appropriate,
reserved for issuance upon such conversion, exchange, redemption or exercise;
and (vi) with respect to shares of Common Stock or Preferred Stock offered,
there will be sufficient shares of Common Stock or Preferred Stock authorized
under the Company's Charter Documents and not otherwise reserved for issuance.

     Based upon and subject to the foregoing and subject also to the comments,
assumptions and qualifications set forth below, we are of the opinion that:

     1. The Company is a corporation duly incorporated, validly existing and in
good standing under the laws of the State of Delaware.

     2. With respect to Debt Securities to be issued under a senior securities
indenture, when (i) such senior securities indenture has been duly qualified
under the Trust Indenture Act of 1939, as amended (the "TIA"); (ii) the
applicable trustee has been qualified under the TIA and an applicable Form T-1
has been properly filed with the Commission; (iii) the Board of Directors of the
Company or, to the extent permitted by the Delaware General Corporation Law (the
"DGCL") and the Charter Documents, a duly constituted and acting committee
thereof (such Board of Directors or committee being hereinafter referred to as
the "Board") has taken all necessary corporate action to approve and establish
the terms of such Debt Securities and to approve the issuance thereof, the terms
of the offering thereof and related matters; (iv) the terms of such Debt
Securities and of their issuance and sale have been established so as not to
violate any applicable law or result in a default under or breach of any
agreement or instrument binding upon the Company and so as to comply with any
requirement or restriction imposed by any court or governmental body having
jurisdiction over the Company; and (v) such Debt Securities have been duly
executed, authenticated, issued and delivered in accordance with both the
provisions of such senior debt indenture and either (a) the provisions of the
applicable definitive purchase, underwriting or similar agreement approved by
the Board upon payment of the consideration therefor provided for therein or (b)
upon conversion, exchange, redemption or exercise of any other Security, in
accordance with the terms of such Security or the instrument governing such
Security providing for such conversion, exchange, redemption or exercise as
approved by the Board, for the consideration approved by the Board, such Debt
Securities will be legally issued and will constitute valid and binding
obligations of the Company, enforceable against the Company in accordance with
their terms.

     3. With respect to Debt Securities to be issued under a subordinated
securities indenture, when (i) such subordinated securities indenture has been
duly qualified under the TIA; (ii) the applicable trustee has been qualified
under the TIA and an applicable Form T-1 has been properly filed with the
Commission; (iii) the Board has taken all necessary corporate action to approve
and establish the terms of such Debt Securities and to approve the issuance
thereof, the terms of the offering thereof and related matters; (iv) the terms
of such Debt Securities and of their issuance and sale have been established so
as not to violate any applicable law or result in a default under or breach of
any agreement or instrument binding upon the Company and so as to comply with
any requirement or restriction imposed by any court or governmental body having
jurisdiction over the Company; and (v) such Debt Securities have been duly
executed, authenticated, issued and delivered in accordance with both the
provisions of such subordinated debt indenture and either (a) in accordance with
the provisions of the applicable definitive purchase, underwriting or similar
agreement approved by the Board upon payment of the consideration therefor
provided for therein or (b) upon conversion, exchange, redemption or exercise of
any other Security, in accordance with the terms of such Security or the
instrument governing such Security providing for such conversion, exchange,
redemption or exercise as approved by the Board, for the consideration approved
by the Board, such Debt Securities will be legally issued and will constitute
valid and binding obligations of the Company, enforceable against the Company in
accordance with their terms.

     4. Pursuant to the Charter, the Company is authorized to issue up to
5,000,000 shares of Preferred Stock. Assuming that the aggregate number of
shares of Preferred Stock issued and sold pursuant to the Registration Statement
by the Company, along with all other shares of Preferred Stock issued by the
Company or reserved for issuance, does not exceed 5,000,000 shares (or such
other number of shares of Preferred Stock as may then be authorized for issuance
under the Charter), when (i) the Board has taken all necessary corporate action
to approve and establish the terms of the shares of Preferred Stock and to
approve the issuance, and the terms of the offering thereof and related matters,
including the adoption of a Certificate of Designation relating to such
Preferred Stock (a "Certificate of Designation") and the filing of such
Certificate of Designation with the Secretary of State of the State of Delaware
in accordance with the DGCL, and (ii) certificates representing the shares of
Preferred Stock have been duly executed, countersigned, registered and delivered
either (a) in accordance with the applicable definitive purchase, underwriting
or similar agreement approved by the Board upon payment of the consideration
therefor (not less than the par value of the Preferred Stock) provided for
therein, or (b) upon conversion, exchange, redemption or exercise of any other
Security, in accordance with the terms of such Security or the instrument
governing such Security providing for such conversion, exchange, redemption or
exercise as approved by the Board, for the consideration approved by the Board
(not less than the par value of the Preferred Stock), the shares of Preferred
Stock will be duly authorized, validly issued, fully paid and non-assessable.

     5. Pursuant to the Charter, the Company is authorized to issue up to
125,000,000 shares of Common Stock. Assuming that the aggregate number of shares
of Common Stock issued and sold pursuant to the Registration Statement by the
Company, along with all other shares of Common Stock from time to time issued
and outstanding or reserved for issuance, does not exceed 125,000,000 shares (or
such other number of shares of Common Stock as may then be authorized for
issuance under the Charter), when (i) the Board has taken all necessary
corporate action to approve the issuance thereof, the terms of the offering of
shares of Common Stock and related matters, and (ii) certificates representing
the shares of Common Stock have been duly executed, countersigned, registered
and delivered either (a) in accordance with the applicable definitive purchase,
underwriting or similar agreement approved by the Board upon payment of the
consideration therefor (not less than the par value of the Common Stock)
provided for therein, or (b) upon conversion, exchange, redemption or exercise
of any other Security, in accordance with the terms of such Security or the
instrument governing such Security providing for such conversion, exchange,
redemption or exercise as approved by the Board, for the consideration approved
by the Board (not less than the par value of the Common Stock and, in the case
of shares of Common Stock issued upon the conversion, exchange or exercise of
another security, the consideration specified in the DGCL), the shares of Common
Stock will be duly authorized, validly issued, fully paid and non-assessable.

     6. With respect to Warrants, when (i) the Board has taken all necessary
corporate action to approve and establish the terms of such Warrants and to
approve the issuance thereof, the terms of the offering thereof and related
matters; (ii) the terms of such Warrants and of their issuance and sale have
been established so as not to violate any applicable law or result in a default
under or breach of any agreement or instrument binding upon the Company and so
as to comply with any requirement or restriction imposed by any court or
governmental body having jurisdiction over the Company; (iii) the warrant
agreement relating to the Warrants has been duly authorized and validly executed
and delivered by the Company and the warrant agent appointed by the Company; and
(iv) the Warrants or certificates representing the Warrants have been duly
executed, countersigned, registered and delivered in accordance with such
warrant agreement and the applicable definitive purchase, underwriting or
similar agreement approved by the Board and upon payment of the consideration
therefor provided for therein, the Warrants will be validly issued.

     7. With respect to Rights, when (i) the Board has taken all necessary
corporate action to approve and establish the terms of such Rights and to
approve the issuance thereof, the terms of the offering thereof and related
matters; (ii) the terms of such Rights and of their issuance and sale have been
established so as not to violate any applicable law or result in a default under
or breach of any agreement or instrument binding upon the Company and so as to
comply with any requirement or restriction imposed by any court or governmental
body having jurisdiction over the Company; (iii) the rights agreement relating
to the Rights has been duly authorized and validly executed and delivered by the
Company and the rights agent appointed by the Company; and (iv) the Rights or
certificates representing the Rights have been duly executed, countersigned,
registered and delivered in accordance with such rights agreement and the
applicable definitive purchase, underwriting or similar agreement approved by
the Board and upon payment of the consideration therefor provided for therein,
the Rights will be validly issued.

     8. With respect to Purchase Contracts, when (i) the Board has taken all
necessary corporate action to approve and establish the terms of the Purchase
Contracts and to approve the issuance thereof, the terms of the offering and
related matters; (ii) the terms of such Purchase Contracts and of their issuance
and sale have been established so as not to violate any applicable law or result
in a default under or breach of any agreement or instrument binding upon the
Company and so as to comply with any requirement or restriction imposed by any
court or governmental body having jurisdiction over the Company; (iii) the
purchase contract agreement relating to the Purchase Contracts has been duly
authorized and validly executed and delivered by the parties thereto; (iv) the
Purchase Contracts have been duly executed and delivered in accordance with such
purchase contract agreement and the applicable definitive purchase, underwriting
or similar agreement approved by or on behalf of the Board; and (v) any
certificates or receipts representing any securities which are a component of
the Purchase Contracts have been duly executed, countersigned, registered and
delivered in accordance with the purchase contract agreement and the applicable
definitive purchase, underwriting or similar agreement approved by the Board,
and upon payment of the consideration therefor provided for therein, the
Purchase Contracts will be legally issued.

     9. With respect to Units, when (i) the Board has taken all necessary
corporate action to approve and establish the terms of the Units and to approve
the issuance thereof, the terms of the offering and related matters; (ii) the
terms of such Units and of their issuance and sale have been established so as
not to violate any applicable law or result in a default under or breach of any
agreement or instrument binding upon the Company and so as to comply with any
requirement or restriction imposed by any court or governmental body having
jurisdiction over the Company; (iii) the unit agreement relating to the Units
has been duly authorized and validly executed by the parties thereto; (iv) the
Units have been duly executed and delivered in accordance with such unit
agreement and the applicable definitive purchase, underwriting or similar
agreement approved by or on behalf of the Board; and (v) any certificates or
receipts representing any securities which are a component of the Units have
been duly executed, countersigned, registered and delivered in accordance with
such unit agreement and the applicable definitive purchase, underwriting or
similar agreement approved by the Board, and upon payment of the consideration
therefor provided therein, the Units will be legally issued.

     In addition to the limitations set forth above, the opinions set forth
herein are further limited by, subject to and based upon the following:

     (a) Our opinions herein reflect only the application of applicable New York
law, the Federal laws of the United States and, to the extent required by the
foregoing opinions, the DGCL. The Securities may be issued from time to time on
a delayed or continuous basis, but the opinions expressed herein are based upon
the law in effect (and published or otherwise generally available) on the date
hereof, and we assume no obligation to revise or supplement these opinions
should such law be changed by legislative action, judicial decision or
otherwise. In rendering our opinions, we have not considered, and hereby
disclaim any opinion as to, the application or impact of any laws, cases,
decisions, rules or regulations of any other jurisdiction, court or
administrative agency.

     (b) Any opinion set forth herein as to enforceability of the obligations of
the Company may be limited by (i) bankruptcy, insolvency, reorganization,
moratorium or similar laws affecting or relating to the rights and remedies of
creditors generally including, without limitation, laws relating to fraudulent
transfers or conveyances, preferences and equitable subordination, and Section
544 through 550 of the Bankruptcy Code and Sections 270 and 281 of the Debtor
and Creditor Law of the State of New York, (ii) general principles of equity
(regardless of whether considered in a proceeding in equity or at law), (iii) an
implied covenant of good faith and fair dealing, (iv) with respect to any Debt
Securities denominated in a currency other than United States dollars, the
requirement that a claim (or a foreign currency judgement in respect of such a
claim) with respect to such Securities be converted to United States dollars at
a rate of exchange prevailing on a date determined pursuant to applicable law or
governmental authority.

     (c) We express no opinion concerning (i) the validity or enforceability of
any provisions contained in any indentures that purport to waive or not give
effect to rights to notices, defenses, subrogation or other rights or benefits
that cannot be effectively waived under applicable law or (ii) the
enforceability of indemnification provisions to the extent they purport to
relate to liabilities resulting from or based upon negligence or any violation
of federal or state securities or blue sky laws.

     We hereby consent to the filing of this opinion of counsel as an exhibit to
the Registration Statement. We also consent to the reference of the name of our
firm under the heading "Legal Matters" in the Prospectus forming a part of the
Registration Statement. In giving this consent, we do not hereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act.

                                           Very truly yours,

                                           /s/ Bryan Cave LLP