<PAGE>
 
                                                  ------------------------------
                                                        OMB APPROVAL
           UNITED STATES                          OMB NUMBER     3235-0145
SECURITIES AND EXCHANGE COMMISSION                EXPIRES:  DECEMBER 31, 1997
      WASHINGTON, D.C. 20549                      ESTIMATED AVERAGE BURDEN
                                                  HOURS PER RESPONSE . . . 14.90
                                                  ------------------------------


                                  SCHEDULE 13G


                   UNDER THE SECURITIES EXCHANGE ACT OF 1934
                              (AMENDMENT NO. __)*
 
                               Ross Stores, Inc.
- - - --------------------------------------------------------------------------------
                               (Name of Issuer)

                                 Common Stock
- - - --------------------------------------------------------------------------------
                        (Title of Class of Securities)

                                   778296103
                     ------------------------------------
                                (CUSIP Number)


Check the following box if a fee is being paid with this statement [X]. (A fee
is not required only if the filing person: (1) has a previous statement on file
reporting beneficial ownership of more than five percent of the class of
securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7).

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                              PAGE 1 OF 10 PAGES

<PAGE>
 
- - - -------------------                                       ----------------------
CUSIP No. 778296103                  13G                    Page 2 OF 10 Pages
- - - -------------------                                       ----------------------
- - - --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
 
    John Hancock Mutual Life Insurance Company
    I.R.S. No. 04-1414660
- - - --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a) [_]
                                                           (b) [_]
    N/A
- - - --------------------------------------------------------------------------------
 3  SEC USE ONLY


- - - --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION
 
    Commonwealth of Massachusetts
- - - --------------------------------------------------------------------------------
                  5    SOLE VOTING POWER
    Number of   
     Shares            -0-
                ----------------------------------------------------------------
  Beneficially    6    SHARED VOTING POWER
    Owned by    
      Each             -0-
                ----------------------------------------------------------------
    Reporting     7    SOLE DISPOSITIVE POWER
     Person     
      With             -0-
                ----------------------------------------------------------------
                  8    SHARED DISPOSITIVE POWER
                
                       -0-
- - - --------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
    None, except through its indirect, wholly-owned subsidiaries, NM Capital
    Management, Inc., John Hancock Advisers, Inc. and Tucker Anthony
    Incorporated.
- - - --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
 
    N/A
- - - --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
 
    See line 9, above.
- - - --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON*
 
    IC, BD, IA, HC
- - - --------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!
                              PAGE 2 OF 10 PAGES

<PAGE>
 
- - - -------------------                                       ----------------------
CUSIP NO. 778296103                  13G                    PAGE 3 OF 10 PAGES
- - - -------------------                                       ----------------------
- - - --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
 
    John Hancock Subsidiaries, Inc.
    I.R.S. No. 04-2687223
- - - --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a)  [_]
                                                           (b)  [_]
    N/A
- - - --------------------------------------------------------------------------------
 3  SEC USE ONLY


- - - --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION
 
    Delaware
- - - --------------------------------------------------------------------------------
                  5  SOLE VOTING POWER
    Number of   
     Shares          -0-
                ----------------------------------------------------------------
  Beneficially    6  SHARED VOTING POWER
    Owned by    
      Each           -0-
                ----------------------------------------------------------------
    Reporting     7  SOLE DISPOSITIVE POWER
     Person     
      With           -0-
                ----------------------------------------------------------------
                  8  SHARED DISPOSITIVE POWER
                
                     -0-
- - - --------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

    1,239,810: 1,176,710 through its indirect, wholly-owned subsidiary, NM
    Capital Management, Inc., 55,000 through its indirect, wholly-owned
    subsidiary, John Hancock Advisers, Inc. and 8,100 through its indirect,
    wholly-owned subsidiary, Tucker Anthony Incorporated.
- - - --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
 
    N/A
- - - --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
 
    5.1% as stated in Line 9, above.
- - - --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON*
 
    HC
- - - --------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!
                              PAGE 3 OF 10 PAGES

<PAGE>
 
- - - -------------------                                       ----------------------
CUSIP NO. 778296103                  13G                    PAGE 4 OF 10 PAGES
- - - -------------------                                       ----------------------
- - - --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
 
    John Hancock Asset Management
    I.R.S. No. 04-3279774
- - - --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a)  [_]
                                                           (b)  [_]
    N/A
- - - --------------------------------------------------------------------------------
 3  SEC USE ONLY


- - - --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION
 
    Commonwealth of Massachusetts
- - - --------------------------------------------------------------------------------
                  5  SOLE VOTING POWER
    Number of   
     Shares          -0-
                ----------------------------------------------------------------
  Beneficially    6  SHARED VOTING POWER
    Owned by    
      Each           -0-
                ----------------------------------------------------------------
    Reporting     7  SOLE DISPOSITIVE POWER
     Person     
      With           -0-
                ----------------------------------------------------------------
                  8  SHARED DISPOSITIVE POWER
                
                     -0-
- - - -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
    1,231,710: 1,176,710 through its indirect, wholly-owned subsidiary, NM
    Capital Management, Inc. and 55,000 through its indirect, wholly-owned
    subsidiary, John Hancock Advisers, Inc.
- - - --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
 
    N/A
- - - --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
 
    5.1% as stated in line 9.
- - - --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON*
 
    HC
- - - --------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!
                              PAGE 4 OF 10 PAGES

<PAGE>
 
- - - -------------------                                       ----------------------
CUSIP NO. 778296103                  13G                    PAGE 5 OF 10 PAGES
- - - -------------------                                       ----------------------
- - - --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
 
    The Berkeley Financial Group
    I.R.S. No. 04-3145626
- - - --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a)  [_]
                                                           (b)  [_]
    N/A
- - - --------------------------------------------------------------------------------
 3  SEC USE ONLY


- - - --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION
 
    Commonwealth of Massachusetts
- - - --------------------------------------------------------------------------------
                  5   SOLE VOTING POWER
    Number of   
     Shares           -0-
                ----------------------------------------------------------------
  Beneficially    6   SHARED VOTING POWER
    Owned by    
      Each            -0-
                ----------------------------------------------------------------
    Reporting     7   SOLE DISPOSITIVE POWER
     Person     
      With            -0-
                ----------------------------------------------------------------
                  8   SHARED DISPOSITIVE POWER
                
                      -0-
- - - -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
    1,231,710: 1,176,710 through its direct, wholly-owned subsidiary, NM
    Capital Management, Inc. and 55,000 through its direct, wholly-owned
    subsidiary, John Hancock Advisers, Inc.
- - - --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
 
    N/A
- - - --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
 
    5.1%
- - - --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON*
 
    HC
- - - --------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!
                              PAGE 5 OF 10 PAGES

<PAGE>
 
     The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.

Note:  Six copies of this statement, including all exhibits, should be filed
with the Commission.

    ATTENTION:  INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE
FEDERAL CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001)


     Item 1(a)  Name of Issuer:
                -------------- 
                Ross Stores, Inc.

     Item 1(b)  Address of Issuer's Principal Executive Offices:
                ----------------------------------------------- 
                8333 Central Avenue
                Newark, CA  94560-3433

     Item 2(a)  Name of Person Filing:
                --------------------- 

                This filing is made on behalf of John Hancock Mutual Life
                Insurance Company ("JHMLICO"), JHMLICO's wholly-owned
                subsidiary, John Hancock Subsidiaries, Inc. ("JHSI"), JHSI's
                wholly-owned subsidiary, John Hancock Asset Management ("JHAM"),
                and JHAM"s wholly-owned subsidiary, The Berkeley Financial Group
                ("TBFG")

     Item 2(b)  Address of the Principal Offices:
                -------------------------------- 

                The principal business offices of JHMLICO, JHSI, and JHAM are
                located at John Hancock Place, P.O. Box 111, Boston, MA 02117.
                The principal business offices of TBFG is located at 101
                Huntington Avenue, Boston, MA 02199. 

     Item 2(c)  Citizenship:
                ----------- 
                JHMLICO, JHAM and TBFG were organized and exist under the laws
                of the Commonwealth of Massachusetts. JHSI was organized and
                exists under the laws of the State of Delaware.

 
     Item 2(d)  Title of Class of Securities:
                ----------------------------
                Common Stock

     Item 2(e)  CUSIP Number:
                ------------ 
                778296103

     Item 3     If the Statement is being filed pursuant to Rule 13d-1(b), or
                -------------------------------------------------------------
                13d-2(b), check whether the person filing is a:
                ----------------------------------------------

                JHMLICO:  (a) (X) Broker or Dealer registered under (S)15 of the
                                  Act.

                          (c) (X) Insurance Company as defined in (S)3(a)(19) of
                                  the Act.

                          (e) (X) Investment Adviser registered under (S)203 of
                                  the Investment Advisers Act of 1940.

                          (g) (X) Parent Holding Company, in accordance with
                                  (S)240.13d-1(b)(ii)(G).

                              PAGE 6 OF 10 PAGES

<PAGE>
 
                   JHSI:  (g) (X) Parent Holding Company, in accordance with
                                  (S)240.13d-1(b)(ii)(G).
 
                   JHAM:  (g) (X) Parent Holding Company, in accordance with
                                  (S)240.13d-1(b)(ii)(G).
 
                   TBFG:  (g) (X) Parent Holding Company, in accordance with
                                  (S)240.13d-1(b)(ii)(G).
 
 
     Item 4     Ownership:
                -------------
 
                (a)  Amount Beneficially Owned: A direct, wholly-owned
                     -------------------------
                     subsidiary of TBFG, NM Capital Management, Inc. ("NM")
                     beneficially owns 1,176,710 shares of Common Stock in
                     various advisory accounts. NM is an Investment Adviser
                     registered under (S)203 of the Investment Advisers Act of
                     1940. In addition to the shares owned by NM, John Hancock
                     Advisers, Inc. ("JHA"), an Investment Adviser registered
                     under (S)203 of the Investment Advisers Act of 1940 and a
                     direct, wholly-owned subsidiary of TBFG, beneficially owns
                     55,000 shares of Common Stock. Through their parent-
                     subsidiary relationship to NM and JHA, JHMLICO, JHSI, JHAM
                     and TBFG have indirect, beneficial ownership of these same
                     shares.
 
                     The JHA shares are held by the:
 
                     John Hancock Special Value Fund, an open-end diversified
                     management company registered under (S)8 of the Investment
                     Company Act. Under an Advisory Agreement dated October 1,
                     1993, JHA has beneficial ownership of the 52,000 shares
                     held in the fund.                                          
                                          
                     John Hancock Institutional Series Trust - John Hancock
                     Fundamental Value Fund an open-end diversified management
                     company registered under (S)8 of the Investment Company
                     Act. Under an Advisory Agreement dated April 3, 1995, JHA
                     has beneficial ownership of the 3,000 shares held in the
                     fund.
 
                     In addition to the shares beneficially owned by NM and JHA,
                     Tucker Anthony Incorporated ("TA") a Broker/Dealer
                     registered under (S)15 of the Securities Exchange Act of
                     1934, has beneficial ownership of 8,100 shares held in
                     customer accounts. Through their parent-subsidiary
                     relationship to TA, an indirect, wholly-owned subsidiary,
                     JHMLICO and JHSI have indirect, beneficial ownership of the
                     TA shares.

                (b)  Percent of Class:
                     ----------------
                     JHSI - 5.1%
                     TBFG - 5.1%
                     NM - 4.8%
                     JHA - .02%
 
                (c)  (i)  sole power to vote or to direct the vote:
                          NM - 410,600
                          JHA - 55,000
                          TA -   8,100
 
                    (ii)  shared power to vote or to direct the
                          vote:  -0-


                              PAGE 7 OF 10 PAGES

<PAGE>
 
                   (iii)  sole power to dispose or to direct the disposition of:
                          NM - 1,176,710
                          JHA -   55,000
                          TA -     8,100

                    (iv)  shared power to dispose or to direct the disposition
                          of:   -0-

     Item 5     Ownership of Five Percent or Less of a Class:
                -------------------------------------------- 
                Not applicable.

     Item 6     Ownership of More than Five Percent on Behalf of Another
                --------------------------------------------------------
                Person:
                ------
                See Item 4 above.

     Item 7     Identification and Classification of the Subsidiary which
                ---------------------------------------------------------
                Acquired the Security Being Reported on by the Parent Holding
                -------------------------------------------------------------
                Company:
                -------
                See Items 3 and 4 above.

     Item 8     Identification and Classification of Members of the Group:
                --------------------------------------------------------- 
                Not applicable.

     Item 9     Notice of Dissolution of a Group:
                -------------------------------- 
                Not applicable.

     Item 10    Certification:
                ------------- 
                By signing below the undersigned certifies that, to the best of
                its knowledge and belief, the securities referred to above were
                acquired in the ordinary course of business and were not
                acquired for the purpose of and do not have the effect of
                changing or influencing the control of the issuer of such
                securities and were not acquired in connection with or as a
                participant in any transaction having such purpose or effect.


                              PAGE 8 OF 10 PAGES

<PAGE>
 
                                   SIGNATURE


     After reasonable inquiry and to the best of its knowledge and belief, each
of the undersigned certifies that the information set forth in this statement is
true, complete and correct.
 

                                      JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY

                                      By: /s/ John T. Farady
                                          -------------------------------------
                                      Name:   John T. Farady                   
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Senior Vice President & Treasurer
       -------------------                  -----------------------------------


                                      JOHN HANCOCK SUBSIDIARIES, INC.

                                      By: /s/ John T. Farady
                                          -------------------------------------
                                      Name:   John T. Farady                  
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Treasurer                       
       -------------------                  -----------------------------------




                                      JOHN HANCOCK ASSET MANAGEMENT

                                      By: /s/ James H. Young                  
                                          -------------------------------------
                                      Name:   James H. Young                  
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Secretary                       
       -------------------                  -----------------------------------



                                      THE BERKELEY FINANCIAL GROUP

                                      By: /s/ Susan S. Newton
                                          -------------------------------------
                                      Name:   Susan S. Newton                 
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Vice President                  
       -------------------                  -----------------------------------


                              PAGE 9  OF 10 PAGES

<PAGE>
 
                                                                       EXHIBIT A

                             JOINT FILING AGREEMENT
                             ----------------------

     John Hancock Mutual Life Insurance Company, John Hancock Subsidiaries,
Inc., John Hancock Asset Management and The Berkeley Financial Group agree that 
the Initial Schedule 13G, to which this Agreement is attached, relating to the 
Common Stock of Ross Stores, Inc., is filed on behalf of each of them.

 
                                      JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY

                                      By: /s/ John T. Farady
                                          -------------------------------------
                                      Name:   John T. Farady                  
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Senior Vice President & Treasurer
       -------------------                  -----------------------------------


                                      JOHN HANCOCK SUBSIDIARIES, INC.

                                      By: /s/ John T. Farady                  
                                          -------------------------------------
                                      Name:   John T. Farady                  
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Treasurer                       
       -------------------                  -----------------------------------


                                      JOHN HANCOCK ASSET MANAGEMENT

                                      By: /s/ James H. Young                  
                                          -------------------------------------
                                      Name:   James H. Young                  
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Secretary                       
       -------------------                  -----------------------------------


                                      THE BERKELEY FINANCIAL GROUP

                                      By: /s/ Susan S. Newton                 
                                          -------------------------------------
                                      Name:   Susan S. Newton                 
                                           ------------------------------------
Dated:  February 7, 1996              Title:  Vice President                  
       -------------------                  -----------------------------------





                              PAGE 10 OF 10 PAGES