<PAGE>   1
         AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON AUGUST 31, 1999
                                                   REGISTRATION NO. 333-


================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


                             SUN MICROSYSTEMS, INC.
             (Exact name of Registrant as specified in its charter)

              DELAWARE                                    94-28905249
    (State or Other Jurisdiction                        (I.R.S. Employer
   of Incorporation or Organization)                  Identification Number)

                              901 SAN ANTONIO ROAD
                               PALO ALTO, CA 94303
                                 (650) 960-1300
                        (Address, including zip code, of
                    Registrant's principal executive offices)

                    STAR DIVISION CORPORATION 1998 STOCK PLAN
                            (FULL TITLE OF THE PLAN)

                                SCOTT G. MCNEALY
                            CHIEF EXECUTIVE OFFICER
                             SUN MICROSYSTEMS, INC.
                              901 SAN ANTONIO ROAD
                               PALO ALTO, CA 94303
                                 (650) 960-1300
            (Name, address, including zip code and telephone number,
                   including area code, of agent for service)

                                    COPY TO:

                              DAVID J. SEGRE, ESQ.
                              DANIEL R. MITZ, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                               650 PAGE MILL ROAD
                               PALO ALTO, CA 94304
                                 (650) 493-9300



================================================================================



                                       1
<PAGE>   2

                         CALCULATION OF REGISTRATION FEE



<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                         Proposed                 Proposed
                                                         Amount           Maximum                  Maximum            Amount of
                                                          to be        Offering Price             Aggregate          Registration
  Title of Securities to be Registered                 Registered        Per Share             Offering Price             Fee
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                   <C>               <C>                    <C>                   <C>
Common Stock, of the Company to be issued                52,810           $39.90(1)              $2,107,119            $585.78
upon exercise of options granted under the
Star Division Corporation 1998 Stock Plan.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>


(1) Calculated pursuant to Rule 457(h)(1) under the Securities Act of 1933,
    as amended (the "Act"), based on an exercise price of $39.90 per share.




                                        2

<PAGE>   3

                                    PART II:

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT


ITEM 3. INFORMATION INCORPORATED BY REFERENCE.


         There are hereby incorporated by reference in this Registration
Statement the following documents and information heretofore filed with the
Securities and Exchange Commission (the "Commission") by Sun Microsystems, Inc.
(the "Registrant"):

         1. The Registrant's Annual Report on Form 10-K for the year ended June
30, 1998, filed pursuant to Section 13(a) of the Securities Exchange Act of
1934, as amended (the "Exchange Act").

         2. The Registrant's Quarterly Reports on Form 10-Q for the quarters
ended September 27, 1998, December 27, 1998 and March 28, 1999, respectively,
filed pursuant to Section 13(a) of the Exchange Act.

         3. The Registrant's Registration Statement on Form 8-A relating to the
Registrant's Common Stock, filed pursuant to Section 12(b) of the Exchange Act
on October 24, 1986, as amended.

         4. The Registrant's Registration Statement on Form 8-A relating to the
Registrant's Common Share Purchase Rights filed pursuant to Section 12(b) of the
Exchange Act on May 22, 1989, as amended.

         All documents filed by the Registrant pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act after the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities offered have been sold or which deregisters all securities
then remaining unsold, shall be deemed to be incorporated by reference in this
Registration Statement and to be part hereof from the date of filing of such
documents.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the General Corporation Law of the State of Delaware, as
amended, provides that under certain circumstances a corporation may indemnify
any person who was or is a party or is threatened to be made a party to any
threatened, pending or completed action, suit or proceeding whether civil,
criminal, administrative or investigative, by reason of the fact that



                                        3

<PAGE>   4

he or she is or was a director, officer, employee or agent of the Company or is
or was serving at its request in such capacity in another corporation or
business association, against expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement actually and reasonably incurred by him or
her in connection with such action, suit or proceeding if he or she acted in
good faith and in a manner he or she reasonably believed to be in or not opposed
to the best interests of the Company and, with respect to any criminal action or
proceeding, had no reasonable cause to believe his or her conduct was unlawful.

         Section 11 of the Restated Certificate of Incorporation and Bylaws of
the Registrant provides in effect that, subject to certain limited exceptions,
the Registrant shall indemnify its directors and officers to the extent
authorized or permitted by the General Corporation Law of the State of Delaware.
The directors and officers of the Registrant are insured under policies of
insurance maintained by the Company, subject to the limits of the policies,
against certain losses arising from any claims made against them by reason of
being or having been such directors or officers. Like indemnification and
insurance is also provided to those employees of the Registrant who serve as
administrators of the Plan. In addition, the Company has entered into contracts
with certain of its directors providing for indemnification of such persons by
the Registrant to the full extent authorized or permitted by law, subject to
certain limited exceptions.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8. EXHIBITS.


<TABLE>
<CAPTION>
Number          Document
------          --------
<S>            <C>
4.1             Star Division Corporation 1998 Stock Plan.

5.1             Opinion of Wilson Sonsini Goodrich & Rosati, Professional
                Corporation, with respect to the legality of the securities
                being registered.

23.1            Consent of Counsel (Contained in Exhibit 5.1).

23.2            Consent of Ernst & Young LLP, Independent Auditors.

24.1            Power of Attorney (See page 7).
</TABLE>


ITEM 9. UNDERTAKINGS.

         (a) The undersigned Registrant hereby undertakes:

             (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement to include any
material information with respect to the plan of distribution not previously
disclosed in the Registration Statement or any material change to such
information in the Registration Statement.

             (2) That, for the purposes of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
Registration Statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed


                                        4

<PAGE>   5


to be the initial bona fide offering thereof.

         (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

             (b) The undersigned Registrant hereby undertakes that, for purposes
of determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the Registration Statement shall be deemed to be a
new Registration Statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

             (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.



                                        5

<PAGE>   6

                                   SIGNATURES

             Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Sun Microsystems, Inc., a corporation organized and existing under
the laws of the State of Delaware, certifies that it has reasonable grounds to
believe that it meets all of the requirements for filing on Form S-8 and has
duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of Palo Alto, State of
California, on August 31, 1999.

                                         SUN MICROSYSTEMS, INC.



                                         By: /s/ Michael E. Lehman
                                             --------------------------------
                                             Michael E. Lehman,
                                             Vice President, Corporate
                                             Resources and Chief Financial
                                             Officer




                                        6

<PAGE>   7

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Scott G. McNealy and Michael E. Lehman,
jointly and severally, his or her attorneys-in-fact, each with the power of
substitution, for him or her in any and all capacities, to sign any amendments
to this Registration Statement on Form S-8 and to file the same, with exhibits
thereto and other documents in connection therewith, with the Securities and
Exchange Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his or her substitute or substitutes, may do or cause to
be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.


<TABLE>
<CAPTION>
SIGNATURE                                         TITLE                                  DATE
---------                                         -----                                  ----
<S>                                <C>                                              <C>
/s/ Scott G. McNealy               Chairman of the Board of Directors,              August 31, 1999
----------------------------       and Chief Executive Officer
Scott G. McNealy                   (Principal Executive Officer)


/s/ Michael E. Lehman              Vice President, Corporate Resources              August 31, 1999
----------------------------       and Chief Financial Officer
Michael E. Lehman                  (Principal Financial Officer)


/s/ Michael L. Popov               Vice President, Corporate Controller             August 31, 1999
----------------------------       (Principal Accounting Officer)
Michael L. Popov


/s/ James L. Barksdale             Director                                         August 31, 1999
----------------------------
James L. Barksdale


/s/ L. John Doerr                  Director                                         August 31, 1999
----------------------------
L. John Doerr


/s/ Judith L. Estrin               Director                                         August 31, 1999
----------------------------
Judith L. Estrin


/s/ Robert J. Fisher               Director                                         August 31, 1999
----------------------------
Robert J. Fisher


/s/ Robert L. Long                 Director                                         August 31, 1999
----------------------------
Robert L. Long


/s/ M. Kenneth Oshman              Director                                         August 31, 1999
----------------------------
M. Kenneth Oshman


</TABLE>



                                        7

<PAGE>   8

                                INDEX TO EXHIBITS


<TABLE>
<CAPTION>
EXHIBIT
 NUMBER         DESCRIPTION
-------         -----------
<S>            <C>
4.1             Star Division Corporation 1998 Stock Plan.

5.1             Opinion of Wilson Sonsini Goodrich & Rosati, Professional
                Corporation, with respect to the legality of the securities
                being registered.

23.1            Consent of Counsel (Contained in Exhibit 5.1).

23.2            Consent of Ernst & Young LLP, Independent Auditors.

24.1            Power of Attorney (See page 7).
</TABLE>




                                        8
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 15615}]
{"company-data": {"conformed-name": "SUN MICROSYSTEMS INC", "cik": "0000709519", "assigned-sic": "3571", "irs-number": "942805249", "state-of-incorporation": "DE", "fiscal-year-end": "0630"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-86267", "film-number": "99704001"}, "business-address": {"street1": "901 SAN ANTONIO RD", "city": "PALO ALTO", "state": "CA", "zip": "94303", "phone": "6509601300"}, "mail-address": {"street1": "901 SAN ANTONIO ROAD", "city": "PALO ALTO", "state": "CA", "zip": "94303"}}
1
         AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON AUGUST 31, 1999
                                                   REGISTRATION NO. 333-

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                             SUN MICROSYSTEMS, INC.
             (Exact name of Registrant as specified in its charter)

              DELAWARE                                    94-28905249
    (State or Other Jurisdiction                        (I.R.S. Employer
   of Incorporation or Organization)                  Identification Number)

                              901 SAN ANTONIO ROAD
                               PALO ALTO, CA 94303
                                 (650) 960-1300
                        (Address, including zip code, of
                    Registrant's principal executive offices)

                    STAR DIVISION CORPORATION 1998 STOCK PLAN
                            (FULL TITLE OF THE PLAN)

                                SCOTT G. MCNEALY
                            CHIEF EXECUTIVE OFFICER
                             SUN MICROSYSTEMS, INC.
                              901 SAN ANTONIO ROAD
                               PALO ALTO, CA 94303
                                 (650) 960-1300
            (Name, address, including zip code and telephone number,
                   including area code, of agent for service)

                                    COPY TO:

                              DAVID J. SEGRE, ESQ.
                              DANIEL R. MITZ, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                               650 PAGE MILL ROAD
                               PALO ALTO, CA 94304
                                 (650) 493-9300

================================================================================

                                       1
2

                         CALCULATION OF REGISTRATION FEE
---------------------------------------------------------------------------------------------------------------------------------
                                                                         Proposed                 Proposed
                                                         Amount           Maximum                  Maximum            Amount of
                                                          to be        Offering Price             Aggregate          Registration
  Title of Securities to be Registered                 Registered        Per Share             Offering Price             Fee
---------------------------------------------------------------------------------------------------------------------------------
Common Stock, of the Company to be issued                52,810           $39.90(1)              $2,107,119            $585.78
upon exercise of options granted under the
Star Division Corporation 1998 Stock Plan.
---------------------------------------------------------------------------------------------------------------------------------
(1) Calculated pursuant to Rule 457(h)(1) under the Securities Act of 1933,
    as amended (the "Act"), based on an exercise price of $39.90 per share.

                                        2
3

                                    PART II:

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

ITEM 3. INFORMATION INCORPORATED BY REFERENCE.

         There are hereby incorporated by reference in this Registration
Statement the following documents and information heretofore filed with the
Securities and Exchange Commission (the "Commission") by Sun Microsystems, Inc.
(the "Registrant"):

         1. The Registrant's Annual Report on Form 10-K for the year ended June
30, 1998, filed pursuant to Section 13(a) of the Securities Exchange Act of
1934, as amended (the "Exchange Act").

         2. The Registrant's Quarterly Reports on Form 10-Q for the quarters
ended September 27, 1998, December 27, 1998 and March 28, 1999, respectively,
filed pursuant to Section 13(a) of the Exchange Act.

         3. The Registrant's Registration Statement on Form 8-A relating to the
Registrant's Common Stock, filed pursuant to Section 12(b) of the Exchange Act
on October 24, 1986, as amended.

         4. The Registrant's Registration Statement on Form 8-A relating to the
Registrant's Common Share Purchase Rights filed pursuant to Section 12(b) of the
Exchange Act on May 22, 1989, as amended.

         All documents filed by the Registrant pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act after the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities offered have been sold or which deregisters all securities
then remaining unsold, shall be deemed to be incorporated by reference in this
Registration Statement and to be part hereof from the date of filing of such
documents.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the General Corporation Law of the State of Delaware, as
amended, provides that under certain circumstances a corporation may indemnify
any person who was or is a party or is threatened to be made a party to any
threatened, pending or completed action, suit or proceeding whether civil,
criminal, administrative or investigative, by reason of the fact that

                                        3
4

he or she is or was a director, officer, employee or agent of the Company or is
or was serving at its request in such capacity in another corporation or
business association, against expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement actually and reasonably incurred by him or
her in connection with such action, suit or proceeding if he or she acted in
good faith and in a manner he or she reasonably believed to be in or not opposed
to the best interests of the Company and, with respect to any criminal action or
proceeding, had no reasonable cause to believe his or her conduct was unlawful.

         Section 11 of the Restated Certificate of Incorporation and Bylaws of
the Registrant provides in effect that, subject to certain limited exceptions,
the Registrant shall indemnify its directors and officers to the extent
authorized or permitted by the General Corporation Law of the State of Delaware.
The directors and officers of the Registrant are insured under policies of
insurance maintained by the Company, subject to the limits of the policies,
against certain losses arising from any claims made against them by reason of
being or having been such directors or officers. Like indemnification and
insurance is also provided to those employees of the Registrant who serve as
administrators of the Plan. In addition, the Company has entered into contracts
with certain of its directors providing for indemnification of such persons by
the Registrant to the full extent authorized or permitted by law, subject to
certain limited exceptions.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8. EXHIBITS.
Number          Document
------          --------
4.1             Star Division Corporation 1998 Stock Plan.

5.1             Opinion of Wilson Sonsini Goodrich & Rosati, Professional
                Corporation, with respect to the legality of the securities
                being registered.

23.1            Consent of Counsel (Contained in Exhibit 5.1).

23.2            Consent of Ernst & Young LLP, Independent Auditors.

24.1            Power of Attorney (See page 7).
ITEM 9. UNDERTAKINGS.

         (a) The undersigned Registrant hereby undertakes:

             (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement to include any
material information with respect to the plan of distribution not previously
disclosed in the Registration Statement or any material change to such
information in the Registration Statement.

             (2) That, for the purposes of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
Registration Statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed

                                        4
5

to be the initial bona fide offering thereof.

         (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

             (b) The undersigned Registrant hereby undertakes that, for purposes
of determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the Registration Statement shall be deemed to be a
new Registration Statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

             (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.

                                        5
6

                                   SIGNATURES

             Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Sun Microsystems, Inc., a corporation organized and existing under
the laws of the State of Delaware, certifies that it has reasonable grounds to
believe that it meets all of the requirements for filing on Form S-8 and has
duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of Palo Alto, State of
California, on August 31, 1999.

                                         SUN MICROSYSTEMS, INC.

                                         By: /s/ Michael E. Lehman
                                             --------------------------------
                                             Michael E. Lehman,
                                             Vice President, Corporate
                                             Resources and Chief Financial
                                             Officer

                                        6
7

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Scott G. McNealy and Michael E. Lehman,
jointly and severally, his or her attorneys-in-fact, each with the power of
substitution, for him or her in any and all capacities, to sign any amendments
to this Registration Statement on Form S-8 and to file the same, with exhibits
thereto and other documents in connection therewith, with the Securities and
Exchange Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his or her substitute or substitutes, may do or cause to
be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
SIGNATURE                                         TITLE                                  DATE
---------                                         -----                                  ----
/s/ Scott G. McNealy               Chairman of the Board of Directors,              August 31, 1999
----------------------------       and Chief Executive Officer
Scott G. McNealy                   (Principal Executive Officer)

/s/ Michael E. Lehman              Vice President, Corporate Resources              August 31, 1999
----------------------------       and Chief Financial Officer
Michael E. Lehman                  (Principal Financial Officer)

/s/ Michael L. Popov               Vice President, Corporate Controller             August 31, 1999
----------------------------       (Principal Accounting Officer)
Michael L. Popov

/s/ James L. Barksdale             Director                                         August 31, 1999
----------------------------
James L. Barksdale

/s/ L. John Doerr                  Director                                         August 31, 1999
----------------------------
L. John Doerr

/s/ Judith L. Estrin               Director                                         August 31, 1999
----------------------------
Judith L. Estrin

/s/ Robert J. Fisher               Director                                         August 31, 1999
----------------------------
Robert J. Fisher

/s/ Robert L. Long                 Director                                         August 31, 1999
----------------------------
Robert L. Long

/s/ M. Kenneth Oshman              Director                                         August 31, 1999
----------------------------
M. Kenneth Oshman
7
8

                                INDEX TO EXHIBITS
EXHIBIT
 NUMBER         DESCRIPTION
-------         -----------
4.1             Star Division Corporation 1998 Stock Plan.

5.1             Opinion of Wilson Sonsini Goodrich & Rosati, Professional
                Corporation, with respect to the legality of the securities
                being registered.

23.1            Consent of Counsel (Contained in Exhibit 5.1).

23.2            Consent of Ernst & Young LLP, Independent Auditors.

24.1            Power of Attorney (See page 7).
8