<PAGE>   1


                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                   FORM 10-K/A

[x] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT
    OF 1934 FOR THE FISCAL YEAR ENDED MARCH 31, 2000.

                                       OR

[ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
    ACT OF 1934 FOR THE TRANSITION PERIOD FROM          TO


                        COMMISSION FILE NUMBER: 000-26541
                             GADZOOX NETWORKS, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
                               -------------------

               DELAWARE                                 77-0308899
   (STATE OR OTHER JURISDICTION OF                   (I.R.S. EMPLOYER
    INCORPORATION OR ORGANIZATION)                 IDENTIFICATION NUMBER)


                               5850 HELLYER AVENUE
                           SAN JOSE, CALIFORNIA 95138
          (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES, INCLUDING ZIP CODE)
                                 (408) 360-4950
              (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT: NONE

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: COMMON STOCK,
$.005 PAR VALUE

        Indicate by check mark whether the Registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports) and (2) has been subject to such
requirements for the past 90 days. YES [x] NO [ ]

        Indicate by check mark if disclosure of delinquent filers pursuant to
Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of the Form 10-K or any
amendment to this Form 10-K. [X]

        The aggregate market value of voting stock held by non-affiliates of the
Registrant was approximately $437,335,274 as of May 31, 2000, based upon the
closing price on the Nasdaq National Market reported for such date. This
calculation does not reflect a determination that certain persons are affiliates
of the Registrant for any other purpose. The number of shares outstanding of the
Registrant's common stock on May 31, 2000 was 27,548,334 shares.


<PAGE>   2


                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

        The following table sets forth certain information regarding the
Company's directors and nominees as of March 31, 2000:

<TABLE>
<CAPTION>
                                                                                                                 DIRECTOR
                   NAME                             AGE                           POSITION                         SINCE
                   ----                             ---                           --------                       --------
<S>                                                 <C>      <C>                                                 <C>
Class I directors whose terms expire at
the 2000 Annual Meeting of Stockholders:

    K. William Sickler.........................     51       President, Chief Executive Officer and Director       1996

    Peter Morris(2)............................     54       Director                                              1996

    Denny R.S. Ko(2)...........................     60       Director                                              1994


Class II director whose term expires at
the 2001 annual meeting of stockholders:


    Dr. Milton Chang (1).......................     57       Director                                             1992


Class III directors whose terms expire at
the 2002 annual meeting of stockholders:


    Stephen J. Luczo...........................     43       Director                                             1997

    Robert Kuhling (1).........................     51       Director                                             1996
</TABLE>

----------------------

(1) Member of Compensation Committee.

(2) Member of Audit Committee.

        There is no family relationship between any director or executive
officer of the Company.

        K. William Sickler has served as the Company's President, Chief
Executive Officer and a director since April 1996. From March 1995 to April
1996, Mr. Sickler was executive director of software business development for
Seagate Technology, Inc. ("Seagate"), a software developer and manufacturer of
disk drives. From December 1992 to March 1995, he was president and chief
executive officer of Networking Computing, Inc., a provider of network
management software for local area networks. Mr. Sickler is a member of the
board of directors of Savoir Technology Group, Inc., a distributor of computer,
storage and networking equipment. Mr. Sickler holds a B.S. in engineering from
Princeton University and an M.B.A. from the University of California, Berkeley.

        Peter Morris has served as a director of the Company since September
1996. Mr. Morris is a general partner at New Enterprise Associates, a venture
capital firm, where he has been employed since 1992. Mr. Morris holds a B.S. in
electrical engineering and an M.B.A. from Stanford University.

        Denny R.S. Ko has served as a director of the Company since December
1994. Dr. Ko has been managing general partner of DynaFund Ventures, a venture
capital firm, since August 1997. Dr. Ko is also the chairman of the board of
directors of Dynamics Technology, Inc., a technical research, engineering and
consulting company, which he founded in 1976. Dr. Ko holds a B.S. in mechanical
engineering from National Taiwan University, an M.S. in aeronautics from the
University of California, Berkeley and a Ph.D. in aeronautics and applied
mathematics from the California Institute of Technology.

        Milton Chang has served as a director of the Company since its inception
in April 1992. Dr. Chang is the chairman of the board of directors of New Focus,
Inc., a supplier of photonics tools for laser applications, which he founded in
1990. From 1996 to 1998, Dr. Chang served on the Visiting Committee for Advanced
Technology of the National Institute of Standards and Technology.


<PAGE>   3


Dr. Chang holds a B.S. in electrical engineering from the University of Illinois
and an M.S. and Ph.D. in electrical engineering from the California Institute of
Technology.

        Stephen J. Luczo has served as a director of the Company since June
1997. Mr. Luczo currently serves as chief executive officer, president and a
director of Seagate. Mr. Luczo joined Seagate in October 1993 as senior vice
president, corporate development, was promoted to executive vice president,
corporate development in March 1995, and was promoted to president and chief
operating officer in September 1997, in which capacity he served until August
1998. In July 1998, Mr. Luczo was promoted to the position of chief executive
officer of Seagate and to the board of directors. Mr. Luczo also serves as a
member of the board of directors of Veritas Software Corporation ("Veritas").
Prior to the merger of Veritas and Seagate, Mr. Luczo also served as chairman of
the board of directors of Seagate Software. Prior to becoming Seagate Software's
chairman in July 1997, Mr. Luczo served as Seagate Software's chief operating
officer between March 1995 and July 1997. Mr. Luczo received a M.B.A. from
Stanford University Graduate School of Business and an A.B. from Stanford
University in economics and psychology.

        Robert Kuhling has served as a director of the Company since September
1996. Mr. Kuhling has been a general partner of venture capital funds managed by
ONSET Ventures since 1987. He is a director of Accelerated Networks, a
manufacturer of telecommunications equipment, and Euphonix, Inc., a digital
sound integration company for professional recording studios, as well as several
private companies. Mr. Kuhling holds an M.B.A. from Harvard University and an
A.B. in economics from Hamilton College.

ITEM 11. EXECUTIVE COMPENSATION

EXECUTIVE COMPENSATION

                           SUMMARY COMPENSATION TABLE

        The following Summary Compensation Table sets forth certain information
regarding the compensation of the Chief Executive Officer of the Company, the
other four most highly compensated executive officers of the Company and the
former Chief Technology Officer and the former Chief Strategic Officer of the
Company (the "Named Executive Officers") for services rendered in all capacities
to the Company in the fiscal years ended March 31, 1999 and March 31, 2000.

<TABLE>
<CAPTION>
                                                                                                  LONG-TERM
                                                                                                 COMPENSATION
                                                                                                    AWARDS
                                                                                                 ------------
                                                                    ANNUAL COMPENSATION           SECURITIES
                                                  FISCAL       ---------------------------        UNDERLYING          ALL OTHER
          NAME AND PRINCIPAL POSITION              YEAR        SALARY($)          BONUS($)        OPTIONS(#)       COMPENSATION($)
          ---------------------------             -----        ---------          --------       ------------      ---------------
<S>                                               <C>        <C>                  <C>            <C>               <C>
K. William Sickler(1).......................       2000        $215,000                --           125,000                --
      President and Chief Executive Officer        1999         198,750                --           100,000                --

Kent Bridges................................       2000         138,000           $63,030(2)         15,000                --
      Vice President of Worldwide Sales            1999         137,667            63,451(2)         20,000                --


Wayne Rickard...............................       2000         163,041                --            15,000                --
      Senior Vice President of Research and        1999         143,826                --            45,000                --
      Development

Christine Munson............................       2000         139,747             9,643            15,000                --
      Chief Financial Officer and V.P. of          1999         126,043                --            20,000                --
      Administration

William Hubbard.............................       2000         149,440                --            15,000                --
      Vice President of Manufacturing              1999         137,000                --            20,000                --

Alistair Black..............................       2000         117,360                --            15,000            38,617(3)
      Former Chief Technology Officer              1999         142,500                --            55,000                --

Howie Chin(4)...............................       2000          96,446            33,249(5)         15,000            33,978(6)
      Former Chief  Strategic Officer              1999         125,158                --            20,000                --
</TABLE>


                                      -2-
<PAGE>   4

-------------------------------

(1) In April 1996, Mr. Sickler acquired 1,200,000 shares of restricted stock at
    $0.075 per share, subject to our right to repurchase such shares in the
    event of the termination of his employment. The Company's right to
    repurchase lapses at a rate of 25% of these shares per year. As of March 31,
    2000, Mr. Sickler held 50,000 shares of restricted Common Stock subject to
    the Company's right of repurchase, with an aggregate value of $2,397,000
    (based on a per share price of $47.94, the fair market value of the
    Company's Common Stock as of March 31, 2000.) No dividends will be paid on
    this stock.

(2) Represents sales commissions and bonus.

(3) In November 1999, Mr. Black resigned as Chief Technical Officer. The sum
    represented above is for consulting fees paid to Mr. Black for services
    rendered.

(4) In November 1995, Mr. Chin acquired 200,000 shares subject to the Company's
    right of repurchase in the event of his termination. The Company's right of
    repurchase lapses at a rate of 25% of these shares per year. As of March 31,
    2000, Mr. Chin held no shares of restricted common stock subject to the
    Company's right of repurchase.

(5) In December 1999, Mr. Chin resigned as Chief Strategic Officer. The sum
    represented above is for severance paid to Mr. Chin.

(6) The sum represented above is for consulting fees paid to Mr. Chin for
    services rendered.

OPTION GRANTS IN LAST FISCAL YEAR

        The following table sets forth certain information for each grant of
options to purchase the Company's Common Stock during fiscal 2000 to each of the
Named Executive Officers. Each of these options granted by the Company was
granted under the 1993 Stock Option Plan, as amended (the "Plan"). Each option
has a term of 10 years, subject to earlier termination in the event the
optionee's services to the Company cease. In accordance with the rules of the
Securities and Exchange Commission, also shown below is the potential realizable
value over the term of the option (the period from the grant date to the
expiration date) based on assumed rates of stock appreciation of 5% and 10%,
compounded annually. These amounts are mandated by the Securities and Exchange
Commission and do not represent the Company's estimate of future stock price.
Actual gains, if any, on stock option exercises will depend on the future
performance of the Company's Common Stock.

<TABLE>
<CAPTION>
                                                             INDIVIDUAL GRANTS                             POTENTIAL REALIZABLE
                                       -----------------------------------------------------------           VALUE AT ASSUMED
                                       NUMBER OF     PERCENT OF TOTAL                                     ANNUAL RATES OF STOCK
                                       SECURITIES    OPTIONS GRANTED      EXERCISE                       APPRECIATION FOR OPTION
                                       UNDERLYING    TO EMPLOYEES IN      PRICE PER                              TERM(5)
                                        OPTIONS           FISCAL            SHARE       EXPIRATION        ----------------------
                NAME                   GRANTED(1)        2000(2)        ($/SHARE)(3)      DATE(4)           5%             10%
                ----                   ----------    ---------------    ------------    ----------        -------      ---------
<S>                                    <C>           <C>                <C>             <C>               <C>          <C>
K. William Sickler................       125,000           10.2%          $  9.00         05/04/09        707,506      1,792,960

Kent Bridges(6)...................        15,000            1.2              9.00         05/04/09         84,901        215,155

Wayne Rickard.....................        15,000            1.2              9.00         05/04/09         84,901        215,155

                                          20,000            1.6             60.75         10/25/09        764,107      1,936,397

Christine Munson..................        15,000            1.2              9.00         05/04/09         84,901        215,155

William Hubbard...................        15,000            1.2              9.00         05/04/09         84,901        215,155

Alistair Black....................        15,000            1.2              9.00         05/04/09         84,901        215,155

Howie Chin........................        15,000            1.2              9.00         05/04/09         84,901        215,155
</TABLE>

-------------------------------

(1) The options for each of the Named Executive Officers vest at the rate of
    2.08% of the shares subject to the option per month, except for the option
    granted to Dr. Black. Dr. Black's option vests at the rate of 3.79% of the
    shares subject to the option per month. Under the Plan, the Board of
    Directors retains the discretion to modify the terms, including the price,
    of outstanding options.

(2) Based on an aggregate of 1,223,550 options granted to employees and
    consultants, including the Named Executive Officers, in fiscal 2000.

(3) Options were granted at an exercise price equal to the fair market value of
    the Company's Common Stock, as determined by reference to the closing price
    reported on the Nasdaq National Market on the date of grant, or as
    determined by the Board of Directors prior to the Company's securities being
    traded on the Nasdaq National Market. The Board of Directors based its
    determination on the Company's financial results and prospects, the share
    price derived for arms-length transactions and evaluations conducted by
    valuation experts.

(4) Options may terminate before their expiration dates if the optionee's status
    as an employee is terminated or upon the optionee's death or disability.

(5) The potential realizable value is net of exercise price before taxes and
    calculated assuming that the fair market value of the Common Stock on the
    date of grant appreciates at the indicated annual rate compounded annually
    for the entire term of the option (ten years) and that the option is
    exercised and sold on the last day of its term for the appreciated stock
    price.

(6) Upon a change of control, 50% of the unvested portion of each stock option
    held by Mr. Bridges will automatically accelerate.


                                      -3-
<PAGE>   5

                 AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR
                        AND FISCAL YEAR-END OPTION VALUES

        The following table sets forth information with respect to the Named
Executive Officers concerning exercisable and unexercisable options held as of
March 31, 2000.

<TABLE>
<CAPTION>
                                                                                                        VALUE OF UNEXERCISED
                                                                      NUMBER OF SECURITIES                   IN-THE-MONEY
                                                                     UNDERLYING UNEXERCISED                   OPTIONS AT
                                  SHARES           VALUE            OPTIONS AT MARCH 31, 2000            MARCH 31, 2000(2)
                               ACQUIRED ON        REALIZED        -----------------------------     -----------------------------
            NAME               EXERCISE (#)        ($)(1)         EXERCISABLE     UNEXERCISABLE     EXERCISABLE     UNEXERCISABLE
            ----               ------------      ---------        -----------     -------------     -----------     -------------
<S>                            <C>               <C>              <C>             <C>               <C>             <C>
K. William Sickler.......              --               --          163,542         153,125          7,506,188        6,341,474
Kent Bridges(3)..........         130,000        4,540,000          156,042          88,958          7,405,146        4,104,742
Wayne Rickard............         100,000        2,255,000          244,584          81,416         11,499,093        2,605,762
Christine Munson.........          20,000          844,000          118,542          66,458          5,604,452        2,026,486
William Hubbard..........          32,309        5,426,995           18,625          83,333            837,683        3,804,718
Alistair Black...........         100,000        4,200,000          128,333          41,667          6,065,922        1,830,953
Howie Chin...............              --               --          135,209          45,791          6,412,576        2,041,341
</TABLE>

-------------------------------

(1) Fair market value of the Company's Common Stock at the exercise date minus
    the per share exercise price.

(2) Based on a value of $47.9375 per share, the fair market value of the
    Company's Common Stock as of March 31, 2000, minus the per share exercise
    price.

(3) Upon a change of control, 50% of the unvested portion of each stock option
    held by Mr. Bridges will automatically accelerate. If a change of control
    had occurred on March 31, 2000, an additional 44,479 shares subject to
    options held by Mr. Bridges would have vested.

CHANGE OF CONTROL, SEVERANCE AND CONSULTING ARRANGEMENTS

        We have entered into a change of control agreement with Kent Bridges. In
the event of a change of control (as defined in the agreement) and regardless of
whether the employment relationship continues following the change of control,
the vesting with respect to a portion of the outstanding stock options issued to
Mr. Bridges will be accelerated and the Company's option to repurchase
applicable to a portion of his restricted stock, if any, will lapse.

        Mr. Bridges' change of control agreement provides that one-half of the
unvested portion of any stock option will be accelerated and the Company's
repurchase option applicable to one-half of any stock subject to such repurchase
option shall lapse upon a change of control. The balance of any unvested shares
not accelerated will continue to vest over the original vesting schedule and the
repurchase option, if any, applicable to any shares will continue to lapse over
the original schedule.

        The change of control agreement provides that if the acceleration of
vesting or lapse of any applicable repurchase option would cause the transaction
resulting in the change of control to not be eligible for accounting treatment
as a "pooling of interests," then the vesting of Mr. Bridges' stock options will
not accelerate and any applicable repurchase option will not lapse on an
accelerated basis.

        In November 1999, Alistair Black resigned as our Chief Technical Officer
and we entered into a Consulting Agreement with Mr. Black for the period from
November 25, 1999 through April 30, 2000. Under the terms of the Consulting
Agreement, Mr. Black provided technical and strategic consulting services in
exchange for consulting fees of approximately $14,353 per month.

        In December 1999, Howey Chin resigned as our Chief Strategic Officer and
was paid severance of approximately $33,249. Additionally, we entered into a
Consulting Agreement with Mr. Chin for the period from December 4, 1999 through
April 30, 2000, pursuant to which Mr. Chin provided strategic marketing
consulting services in exchange for consulting fees of approximately $11,931 per
month.


                                      -4-
<PAGE>   6

DIRECTORS' COMPENSATION

        The Company's non-employee directors are reimbursed for expenses
incurred in connection with attending Board and committee meetings but are not
compensated for their services as Board or committee members. We have in the
past granted non-employee directors options to purchase the Company's Common
Stock pursuant to the terms of the Company's Amended and Restated 1993 Stock
Plan. The Company also grants non-employee directors options to purchase the
Company's Common Stock pursuant to the terms of the Company's 1999 Director
Option Plan (the "Director Plan"). See "Security Ownership of Certain Beneficial
Owners and Management" and "Certain Relationships and Related Transactions -
Executive Officer and Director Option Grants."

        The Director Plan provides for the automatic grant of 5,000 shares of
Common Stock to each non-employee director on the date on which such person
first becomes a non-employee director. Additionally, each non-employee director
shall automatically be granted an option to purchase 2,500 shares of Common
Stock each year on May 1, if on that date he or she has served on the Board for
at least the preceding six months. Each option shall have a term of three years,
and each option is immediately exercisable. The exercise price of all options
shall be 100% of the fair market value per share of the Common Stock, as of the
date of grant. The fair market value per share was determined by the Company's
Board of Directors prior to the existence of a public market for Common Stock.
Thereafter, the fair market value per share has been the price reported on the
Nasdaq Stock Market's National Market as the closing price of Common Stock on
the date of grant or on the last trading day prior to the date of grant, if the
grant is made on a holiday.

        Options granted under the Director Plan must be exercised within three
months after the end of an optionee's tenure as a member of the Board, or within
12 months after his or her death or disability, but in any case not later than
the expiration of the option's term.

REPORT OF THE COMPENSATION COMMITTEE ON EXECUTIVE COMPENSATION

        The following is the report of the Compensation Committee with respect
to the compensation paid to the Company's executive officers during fiscal 2000.
Actual compensation earned during fiscal 2000 by the Named Executive Officers is
shown in the Summary Compensation Table.

        Compensation Philosophy

        The Company operates in the extremely competitive and rapidly changing
high technology industry. The Committee believes that the compensation programs
for its executive officers should be designed to attract, motivate and retain
talented executives responsible for the success of the Company and should be
determined within a competitive framework and based on the achievement of
designated business objectives, individual contribution, customer satisfaction
and financial performance. Within this overall philosophy, the Committee's
objectives are to:

- provide a competitive total compensation package that takes into consideration
  the compensation practices of companies with which the Company competes for
  executive talent; and

- align the financial interests of executive officers with those of stockholders
  by providing executives with an equity stake in the Company.


                                      -5-
<PAGE>   7

        Components of Executive Compensation

        The compensation program for the Company's executive officers consists
of the following components:

        - base salary; and

        - long-term stock option incentives

        Base Salary

        The Compensation Committee reviewed and approved fiscal 2000 salaries
for the Chief Executive Officer and other Named Executive Officers at the
beginning of the fiscal year. Base salaries were established by the Committee
based upon competitive compensation data, an executive's job responsibilities,
level of experience, individual performance and contribution to the business. In
making base salary decisions, the Committee exercised its discretion and
judgment based upon these factors. No specific formula was applied to determine
the weight of each factor. The Committee based its determination of Mr.
Sickler's salary on both his individual performance and the salaries paid to
chief executive officers of peer companies.

        Long- Term Stock Option Incentives

        The Compensation Committee provides the Company's executive officers
with long-term incentive compensation through grants of options to purchase the
Company's Common Stock. The goal of the long-term stock option incentive program
is to align the interests of executive officers with those of the Company's
stockholders and to provide each executive officer with a significant incentive
to manage the Company from the perspective of an owner with an equity stake in
the business. It is the belief of the Committee that stock options directly
motivate an executive to maximize long-term stockholder value. The options also
utilize vesting periods that encourage key executives to continue in employ of
the Company. The Committee considers the grant of each option subjectively,
reviewing factors such as the individual performance, the anticipated future
contribution toward the attainment of the Company's long-term strategic
performance goals and the number of unvested options held by each individual at
the time of the new grant. On May 4, 1999, the Compensation Committee
recommended, and the Board of Directors granted to Mr. Sickler options to
purchase 125,000 shares of common stock at a purchase price of $9.00 per share
and based their decision to grant such options on competitive compensation data,
Mr. Sickler's job responsibilities, anticipated future contribution toward the
attainment of the Company's strategic goals, the number of unvested options held
at the time of the new grant and other factors. No specific formula was applied
to determine the weight of each factor considered.

SECTION 162(m)

        The Company has considered the potential future effects of Section
162(m) of the Internal Revenue Code on the compensation paid to the Company's
executive officers. Section 162(m) disallows a tax deduction for any publicly
held corporation for individual compensation exceeding $1.0 million in any
taxable year for any of the Named Executive Officers, unless compensation is
performance-based. The Company has adopted a policy that, where reasonably
practicable, the Company will seek to qualify the variable compensation paid to
its executive officers for an exemption from the deductibility limitations of
Section 162(m).

        Respectfully submitted by:

        Milton Chang
        Robert Kuhling


                                      -6-
<PAGE>   8

PERFORMANCE GRAPH

        Set forth below is a line graph comparing the annual percentage change
in the cumulative return to the stockholders of the Company's Common Stock with
the cumulative return of the Nasdaq Stock Market (U.S.) Index and of the Nasdaq
Electronic Components Index for the period commencing July 20, 1999 and ending
on March 31, 2000. Returns for the indices are weighted based on market
capitalization at the beginning of each measurement point. The graph assumes
that $100 was invested on July 20, 1999 in the Company's Common Stock, the
Nasdaq Stock Market (U.S.) Index and the Nasdaq Electronic Components Index and
that all dividends were reinvested. No dividends have been declared or paid on
the Company's Common Stock. Stockholder returns over the indicated period should
not be considered indicative of future stockholder returns.





                              [PERFORMANCE GRAPH]





                            Cumulative Total Return

<TABLE>
<CAPTION>
7/20/99      7/99      8/99      9/99       10/99       11/99       12/99       1/00       2/00       3/00
-------     ------    ------    ------      ------      ------      ------     ------     ------     ------
<S>         <C>       <C>       <C>         <C>         <C>         <C>        <C>        <C>        <C>
100.00      358.33    430.36    256.55      226.79      376.19      207.44     180.95     315.48     228.28
100.00       96.47    100.53    100.63      108.69      121.87      148.66     143.26     170.47     166.93
100.00      104.16    120.13    112.72      123.18      131.72      150.04     173.90     228.69     241.19
</TABLE>


           The information contained above under the captions "Report of the
Compensation Committee on Executive Compensation" and "Performance Graph" shall
not be deemed to be "soliciting material" or to be "filed" with the Securities
and Exchange Commission, nor shall such information be incorporated by reference
into any future filing under the Securities Act of 1933, as amended, or the
Securities Exchange Act of 1934, as amended, except to the extent that the
Company specifically incorporates it by reference into such filing.


                                      -7-
<PAGE>   9

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

                          SECURITY OWNERSHIP OF CERTAIN
                        BENEFICIAL OWNERS AND MANAGEMENT

        The following table sets forth certain information regarding the
beneficial ownership of Common Stock of the Company as of June 30, 2000 as to
(i) each person who is known by the Company to own beneficially more than 5% of
the outstanding shares of Common Stock, (ii) each director and nominee for
director of the Company, (iii) each of the executive officers named in the
Summary Compensation Table below and (iv) all directors and executive officers
of the Company as a group. Unless otherwise indicated, the address of each
listed stockholder is c/o Gadzoox Networks, Inc., 5850 Hellyer Avenue, San Jose,
California 95138.


<TABLE>
<CAPTION>
                                                                            NUMBER OF SHARES                   PERCENT OF SHARES
NAME AND ADDRESS OF BENEFICIAL OWNER                                     BENEFICIALLY OWNED(1)               BENEFICIALLY OWNED(1)
--------------------------------------                                   ---------------------------         ---------------------
<S>                                                                      <C>                                 <C>
NAMED EXECUTIVE OFFICERS AND DIRECTORS

K. William Sickler (2)                                                          1,450,546                            5.24%

Kent Bridges(3)                                                                   295,105                            1.06

Wayne Rickard (4)                                                                 310,833                            1.12

Christine E. Munson (5)                                                           150,938                            *

William Hubbard (6)                                                               109,459                            *

Alistair Black (7)                                                               1,007,23                            3.65
   18164 Via Encantada
   Monte Sereno, CA 95030

Howie Chen (8)                                                                    125,000                            *
   10081 Bret Avenue
   Cupertino, CA 95014

Stephen Luczo (9)                                                               5,287,973                            19.17
   c/o Seagate Technology
   920 Disc Drive, Building One
   Scotts Valley, CA 95066

Peter Morris (10)                                                                 850,936                             3.08
   c/o New Enterprise Associates
   2490 Sand Hill Road
   Menlo Park, CA 94025

Rob Kuhling (11)                                                                  149,638                             *
   c/o ONSET Ventures
   2490 Sand Hill Road
   Menlo Park, CA 94025

Milton Chang (12)                                                               1,110,821                             4.03
   c/o New Focus, Inc.
   2630 Walsh Avenue
   Santa Clara, CA 95051

Denny R.S. Ko (13)                                                              1,288,706                             4.67
   c/o Dynamics Technology, Inc.
   21311 Hawthorne Boulevard
   Suite 300
   Torrance, CA 90503-5610

5% STOCKHOLDERS

Seagate Technologies, Inc.                                                      5,274,015                            19.12
   920 Disc Drive, Building One
   Scotts Valley, CA 95066
</TABLE>


                                      -8-
<PAGE>   10


<TABLE>
<CAPTION>
                                                                            NUMBER OF SHARES                   PERCENT OF SHARES
NAME AND ADDRESS OF BENEFICIAL OWNER                                     BENEFICIALLY OWNED(1)               BENEFICIALLY OWNED(1)
--------------------------------------                                   ---------------------------         ---------------------
<S>                                                                      <C>                                 <C>
NAMED EXECUTIVE OFFICERS AND DIRECTORS

Entities associated with Galleon Technology Partners II, L.P. (14)              1,613,300                             5.85
   135 E. 57th Street
   New York NY 10022

All executive officers and directors as a group (13 persons) (15)              16,271,021                            57.52
</TABLE>

-------------------------------

 *  Less than 1%

(1)  Applicable percentage ownership is based on 27,584,719 shares of Common
     Stock outstanding as of June 30, 2000, together with applicable options for
     such stockholder. Beneficial ownership is determined in accordance with the
     rules of the Securities and Exchange Commission (the "Commission"), and
     includes voting and investment power with respect to shares. Shares of
     Common Stock subject to options currently exercisable or exercisable within
     60 days after June 30, 2000 are deemed outstanding for computing the
     percentage ownership of the person holding such options, but are not deemed
     outstanding for computing the percentage of any other person. Except as
     noted in the footnotes to this table, and subject to applicable community
     property laws, the persons named in the table have sole voting and
     investment power with respect to all shares of the Company's Common Stock
     shown as beneficially owned by them.

(2)  Represents 95,312 shares issuable upon exercise of options held by Mr.
     Sickler exercisable within 60 days of June 30, 2000, 1,341,605 shares held
     by K. William Sickler and Gail A. Sickler, Trustees UTA Dated July 16,
     1992, 4,543 shares held by K. William Sickler, Trustee, or his successor
     under the Brett Ellen Sickler Trust, 4,543 shares held by K. William
     Sickler, Trustee, or his successor under the Cole William Sickler Trust,
     and 4,543 shares held by K. William Sickler, Trustee, or his successor
     under the Joanna Jackson Sickler Trust. Of the 1,249,938 shares held by K.
     William Sickler and Gail A. Sickler, Trustees UTA dated July 16, 1992,
     2,000 shares are subject to the Company's right of repurchase as of June
     30, 2000, which right lapses over time. Mr. Sickler disclaims beneficial
     ownership of the shares held in trust for his children.

(3)  Includes 145,105 shares issuable upon exercise of options held by Mr.
     Bridges exercisable within 60 days of June 30, 2000.

(4)  Includes 260,833 shares issuable upon exercise of options held by Mr.
     Rickard exercisable within 60 days of June 30, 2000.

(5)  Includes 140,938 shares issuable upon exercise of options held by Ms.
     Munson exercisable within 60 days of June 30, 2000.

(6)  Includes 19,497 shares issuable upon exercise of options held by Mr.
     Hubbard exercisable within 60 days of June 30, 2000.

(7)  Based solely on a Form 4 filed with the SEC on March 9, 2000. Represents
     970,202 shares held by The Savage/ Black Living Trust, Alistair D. Black
     and Deborah A. Savage, Trustees, 18,518 shares held by Alistair Black,
     custodian for Duncan Oliver Black, under the California Uniform Transfers
     to Minors Act and 18,518 shares held by Alistair Black, custodian for Dylan
     Savage Black, under the California Uniform Transfers to Minors Act. Mr.
     Black disclaims beneficial ownership of the shares held by him as custodian
     for his children.

(8)  Based solely on a Form 4 filed with the SEC on March 9, 2000.

(9)  Mr. Luczo is the chief executive officer of Seagate and a director of the
     Company. Represents 5,274,015 shares held by Seagate, 8,333 shares of
     Common Stock held by Mr. Luczo and 5,625 shares issuable upon exercise of
     options held by Mr. Luczo exercisable within 60 days of June 30, 2000. Mr.
     Luczo disclaims beneficial ownership of shares held by Seagate.

(10) Mr. Morris is a general partner of New Enterprise Associates VIII and a
     director of the Company. Represents 494,446 shares held by New Enterprise
     Associates VI, Limited Partnership, 324,317 shares held by New Enterprise
     Associates VIII, Limited Partnership, 2,500 shares held by NEA Presidents
     Fund, L.P., 64 shares held by NEA Onset Partners III LP, 22,109 shares held
     by Mr. Morris and 7,500 shares issuable upon exercise of options held by
     Mr. Morris exercisable within 60 days of June 30, 2000. Mr. Morris
     disclaims beneficial ownership of shares held by these entities, except for
     his proportional interest arising from his partnership interest in such
     funds.

(11) Mr. Kuhling is a general partner of ONSET Ventures and a director of the
     Company. Represents 83,190 shares held by ONSET Enterprise Associates II,
     L.P., 57,828 shares held by Robert Frank Kuhling, Jr. and Michele Denise
     Wilcox, Co-Trustees of the Kuhling-Wilcox 1990 Trust, 1,120 shares held by
     Mr. Kuhling and 7,500 shares issuable upon exercise of options held by Mr.
     Kuhling exercisable within 60 days of June 30, 2000. Mr. Kuhling disclaims
     beneficial ownership of shares held by ONSET, except to the extent of his
     proportional interest arising from his partnership interest in ONSET.

(12) Represents 1,103,321 shares held by Dr. Chang and 7,500 shares issuable
     upon exercise of options held by Dr. Chang exercisable within 60 days of
     June 30, 2000.

(13) Dr. Ko is the chairman of Dynamics Technology, Inc. ("Dynamics") and a
     director of the Company. Represents 1,259,206 shares held by Dynamics,
     22,000 shares issuable upon exercise of options held by Dynamics and 7,500
     shares issuable upon exercise of options held by Dr. Ko exercisable within
     60 days of June 30, 2000. Dr. Ko disclaims beneficial ownership of the
     shares held by Dynamics except to the extent of his proportional interest
     therein.

(14) Includes 81,983 shares held by Galleon Technology Partners I, L.P., 311,380
     shares held by Galleon Technology Partners II, L.P., 90,850 shares held by
     Galleon New Media Partners, L.P. and 1,129,087 shares held by Galleon
     Management, L.P.

(15) Includes 702,082 shares issuable upon exercise of options held by these
     individuals exercisable within 60 days of June 30, 2000. Of the 16,271,021
     shares held by these individuals, 2,000 shares are subject to the Company's
     right of repurchase as of June 30, 2000, which right lapses over time.


------------------------


*  Less than one percent of the outstanding Common Stock.


                                      -9-
<PAGE>   11

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

        Since the beginning of the Company's last fiscal year, there has not
been nor is there currently proposed any transaction or series of similar
transactions to which the Company was or is to be a party in which the amount
involved exceeds $60,000 and in which any director, executive officer, holder of
more than 5% of the Common Stock of the Company or any member of the immediate
family of any of the foregoing persons had or will have a direct or indirect
material interest other than (1) compensation agreements and other arrangements,
which are described where required in "Change of Control, Severance and
Consulting Arrangements" and (2) the transactions described below.

TRANSACTIONS WITH DIRECTORS, EXECUTIVE OFFICERS AND 5% STOCKHOLDERS

        Pursuant to a sale and rights transfer agreement dated as of May 26,
1999, a third-party investor sold all of the shares of the Company's capital
stock that it held, a total of 784,314 shares of Series H preferred stock, to
three investors. Of these 784,314 shares, the third-party investor sold 459,317
shares to New Enterprise Associates VIII, Limited Partnership, 2,500 shares to
N.E.A. Presidents Fund, L.P. and 322,497 shares to ONSET Enterprise Associates
III, L.P., at a per share purchase price of $10.00 for an aggregate purchase
price of $7,843,140. Peter Morris, a director of the Company, is a partner of
New Enterprise Associates. Mr. Morris disclaims any beneficial ownership of the
securities held by New Enterprise Associates VIII, Limited Partnership and
N.E.A. Presidents Fund, L.P., except to the extent of his proportional
partnership interest in these entities. Rob Kuhling, a director of the Company,
is a partner with ONSET Enterprise Associates. Mr. Kuhling disclaims any
beneficial ownership of the securities held by ONSET Enterprise Associates III,
L.P., except to the extent of his proportional partnership interest in this
entity.

LOAN TO EXECUTIVE OFFICER

        On June 26, 2000 the Company loaned $285,000 to Clark S. Foy, the
Company's Vice President of Marketing. The outstanding principal balance accrues
interest at the rate of 6% per annum and is due on June 26, 2004. The sum of
$17,812.50 shall be payable quarterly; however, this amount shall be forgiven as
and when it becomes due so long as Mr. Foy remains an employee of the Company.

EXECUTIVE OFFICER AND DIRECTOR OPTION GRANTS

        On various occasions during fiscal 2000, the Company granted the
following options to purchase Common Stock to the following current and former
executive officers and directors of the Company:

<TABLE>
<CAPTION>
                                NAME                              DATE OF GRANT       NUMBER OF OPTIONS    EXERCISE PRICE/ SHARE
                                ----                              -------------       -----------------    ---------------------
<S>                                                               <C>                 <C>                  <C>
Stephen Luczo...............................................          5/4/99                5,000                  9.00
                                                                      5/1/00                2,500                 37.56

Peter Morris................................................          5/4/99                5,000                  9.00
                                                                      5/1/00                2,500                 37.56

Rob Kuhling.................................................          5/4/99                5,000                  9.00
                                                                      5/1/00                2,500                 37.56

Denny Ko....................................................          5/4/99                5,000                  9.00
                                                                      5/1/00                2,500                 37.56

Milton Chang................................................          5/4/99                5,000                  9.00
                                                                      5/1/00                2,500                 37.56

K. William Sickler..........................................          5/4/99              125,000                  9.00

Alistair Black..............................................          5/4/99               15,000                  9.00

Howey Chin..................................................          5/4/99               15,000                  9.00

Christine E. Munson.........................................          5/4/99               15,000                  9.00

Kurt Chan...................................................          5/4/99               15,000                  9.00

Wayne Rickard...............................................          5/4/99               15,000                  9.00

Kent Bridges................................................          5/4/99               15,000                  9.00

David Tang..................................................          5/4/99               50,000                  9.00

William Hubbard.............................................          5/4/99               15,000                  9.00
</TABLE>


                                      -10-
<PAGE>   12

RELATIONSHIP WITH SEAGATE TECHNOLOGY, INC.

        The Company has developed a strategic partnership with Seagate
Technology, Inc. ("Seagate Technology") pursuant to which the Company has
collaborated with Seagate Technology on the development of industry standards,
the design and development of new SAN products, the interoperability of
products, strategic planning and SAN market development. In addition, Seagate
Technology has made several investments in the Company as described below.
Stephen J. Luczo, a director, is also the chief executive officer of Seagate
Technology.

        On September 18, 1998, the Company entered into a $15,000,000
convertible note purchase agreement with Seagate Technology. The convertible
note bears simple interest of 5.75% per annum with principal and interest
maturing on September 18, 2001. The Company has the option to convert any
portion of the outstanding balance of principal and interest into Common Stock
at a price per share of $7.65. Since September 18, 1998, the Company has
converted approximately $12,766,000 of accrued interest and principal into
1,668,722 shares of Common Stock under the convertible note. At June 30, 2000,
the Company owed approximately $3,038,000 in accrued interest and principal
under the convertible note which, if converted, would have converted into
approximately 397,121 shares of Common Stock. In June 2000, the Company notified
Seagate Technology of its intention to repay, on July 31, 2000, the outstanding
accrued interest and principal balance under the convertible note, which is
estimated to be approximately $3,111,000.

        Pursuant to an agreement that the Company entered into with Seagate
Technology and a third-party investor (which third-party investor subsequently
sold all of its shares of Common Stock to funds affiliated with New Enterprise
Associates and ONSET Ventures) on October 12, 1998, Seagate Technology agreed to
certain restrictions on its ownership of Common Stock. Specifically, unless the
Board consents, Seagate Technology has agreed not to:

        - acquire beneficial ownership of any shares of the Company's capital
          stock if after acquiring the shares, Seagate Technology would
          beneficially own more than 19.9% of the Company's outstanding voting
          stock;

        - form, join or in any way participate in a group acting together for
          the purpose of acquiring, holding or disposing of shares of the
          Company's capital stock if the group beneficially owns more than 5% of
          the Company's outstanding voting stock;

        - submit any resolution to the Company's stockholders or become a
          participant in a proxy solicitation in opposition to the
          recommendation of a majority of the Company's directors; or

        - enter into any voting arrangement with respect to any shares of the
          Company's capital stock.

        In addition, if Seagate Technology acquires more than 19.9% of the
Company's voting stock the Company has the right to purchase from Seagate
Technology a sufficient number of shares of voting stock so as to reduce the
voting stock held by Seagate Technology to no more than 19.9% of the Company's
outstanding voting stock. To purchase shares held by Seagate Technology pursuant
to this right, the Company would have to pay the average per share cash price
paid by Seagate Technology calculated on a last purchased, first sold basis.

        These limitations on Seagate Technology's ownership of the Company's
capital stock expire upon the earlier to occur of (1) July 19, 2002, (2) when a
tender offer is made for not less than 50% of the Company's outstanding shares
or (3) when another entity or group acquires not less than 25% ownership of the
total combined voting power of all of the Company's outstanding shares.


                                      -11-
<PAGE>   13

        Pursuant to the stockholders' agreement, Seagate Technology agreed that
it will not, nor will it permit any of its affiliates to, sell or transfer any
shares of the Company's capital stock to a person or entity that is engaged in
or has publicly announced its intention to enter into the business of
developing, manufacturing, marketing or selling storage area networks.

        In addition, for so long as Seagate Technology owns at least 7% of the
Company's outstanding voting stock, Seagate Technology agreed that it will not,
nor will it permit any of its affiliates to, sell or transfer any shares of the
Company's capital stock, except under the following circumstances:

        - to a person or entity who owned the Company's voting stock immediately
          prior to the closing of the Company's initial public offering;

        - to the Company or to any person approved by the Company;

        - pursuant to a bona fide public offering registered under the
          Securities Act;

        - pursuant to Rule 144 under the Securities Act;

        - pursuant to a bona fide pledge of shares of the Company's capital
          stock to an institutional lender to secure a loan, guarantee or other
          financial support, provided that the lender agrees to hold such stock
          subject to the same restrictions applicable to Seagate Technology or
          the other investor;

        - in the event of a merger or consolidation in which the Company is
          acquired by another corporation, or pursuant to a plan for the
          Company's liquidation;

        - to a wholly-owned subsidiary that has executed an agreement to be
          bound by the same restrictions applicable to Seagate Technology or the
          other investor;

        - sales into any tender or exchange offer (A) which is made by the
          Company or on the Company's behalf; (B) which is made by another
          person or group and is not opposed by the Board; or (C) subject to the
          Company's right of first refusal, which is made by another person or
          group and which would result in such person or group owning more than
          50% of the Company's total outstanding voting stock; or

        - public distributions, provided that, in cases other than public
          distributions underwritten by an underwriter selected by the Company,
          no single purchaser is known to be acquiring more than 5% of our
          outstanding capital stock in the distribution.

        Pursuant to the stockholders' agreement, Seagate Technology granted the
Company certain rights of first refusal with respect to any shares of the
Company's Common Stock held immediately after the closing of the Company's
initial public offering or those shares of Common Stock issuable to Seagate
Technology upon conversion of the convertible note issued to Seagate Technology.
The Company has a right of first refusal to purchase any of these shares sold by
Seagate Technology for so long as Seagate Technology owns at least 7% of the
Company's outstanding voting stock. Certain sales of the Company's voting stock
by Seagate Technology, including sales through a registered public offering, are
not subject to this right of first refusal.


                                      -12-
<PAGE>   14

INDEMNIFICATION

        The Company has entered into indemnification agreements with each of its
directors and officers. Such indemnification agreements require the Company to
indemnify its directors and officers to the fullest extent permitted by Delaware
law.

CONFLICT OF INTEREST POLICY

        The Company believes that all transactions with affiliates described
above were made on terms no less favorable to the Company than could have been
obtained from unaffiliated third parties. The Company's policy is to require
that a majority of the independent and disinterested outside directors on the
Board approve all future transactions between the Company and its officers,
directors, principal stockholders and their affiliates. Such transactions will
continue to be on terms no less favorable to the Company than it could obtain
from unaffiliated third parties.

        All future transactions, including loans, between the Company and its
officers, directors, principal stockholders and their affiliates will be
approved by a majority of the Board, including a majority of the independent and
disinterested outside directors, and will continue to be on terms no less
favorable to the Company than could be obtained from unaffiliated third parties.


                                      -13-
<PAGE>   15

                                   SIGNATURES

        Pursuant to the requirements of Section 13 or 15(d) of the Exchange Act,
the registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                        GADZOOX NETWORKS, INC.

                                        By: /s/ CHRISTINE E. MUNSON
                                           -------------------------------------
                                           Christine E. Munson
                                           Chief Financial Officer
                                           and Vice President of Finance
                                           and Administration

Dated: July 31, 2000

        Pursuant to the requirements of the Exchange Act, this report has been
signed below by the following persons on behalf of the registrant and in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
          SIGNATURE                                                 TITLE                                      DATE
----------------------------                 ------------------------------------------------              -------------
<S>                                          <C>                                                           <C>
              *                              President and Chief Executive Officer (Principal              July 31, 2000
----------------------------                 Executive Officer)
      K. William Sickler


   /s/ CHRISTINE E. MUNSON                   Chief Financial Officer and Vice President of                 July 31, 2000
----------------------------                 Finance and Administration (Principal Financial
     Christine E. Munson                     and Accounting Officer)

              *                              Director                                                      July 31, 2000
----------------------------
        Milton Chang

              *                              Director                                                      July 31, 2000
----------------------------
        Stephen Luczo

              *                              Director                                                      July 31, 2000
----------------------------
          Denny Ko

              *                              Director                                                      July 31, 2000
----------------------------
         Rob Kuhling

              *                              Director                                                      July 31, 2000
----------------------------
        Peter Morris


*By: /s/ CHRISTINE E. MUNSON
----------------------------
     Christine E. Munson
       Attorney-in-fact
</TABLE>