<PAGE>   1




AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 18, 2000.
                                                   REGISTRATION NO. 333-


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
             Registration Statement Under the Securities Act of 1933

                                MASCO CORPORATION
             (Exact Name of Registrant as Specified in its Charter)

         Delaware                                          38-1794485
(State or other jurisdiction of                          (IRS Employer
  incorporation)                                       Identification No.)

                   21001 Van Born Road, Taylor, Michigan 48180
               (Address of Principal Executive Offices) (Zip Code)

              MASCO CORPORATION 1991 LONG TERM STOCK INCENTIVE PLAN
                            (Full Title of the Plan)

                                 JOHN R. LEEKLEY
                    SENIOR VICE PRESIDENT AND GENERAL COUNSEL
                                MASCO CORPORATION
                               21001 VAN BORN ROAD
                             TAYLOR, MICHIGAN 48180
                     (Name and Address of Agent for Service)

                                 (313) 274-7400
           (Telephone no., including area code, of agent for service)

  If any of the securities being registered on this Form are to be offered on a
  delayed or continuous basis pursuant to Rule 415 under the Securities Act of
                       1933, check the following box. [X]

                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
            Title of                   Amount to          Proposed Maximum           Proposed Maximum
        Securities to be                   Be               Offering Price               Aggregate                 Amount of
           Registered               Registered(1)(2)         Per Share(3)            Offering Price(3)        Registration Fee(3)
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                <C>                 <C>                        <C>                       <C>
  Common Stock (Par Value $1.00
         Per Share) (4)                20,000,000              $20.65625                $413,125,000              $125,189.00
-----------------------------------------------------------------------------------------------------------------------------------
</TABLE>


(1)  This Registration Statement registers additional shares of the Registrant's
     common stock issuable pursuant to the same plan for which Registration
     Statements No. 33-42229 and 333-64573 are currently effective. A
     registration fee of $45,250 paid on August 9, 1991 with the original filing
     to register 16,000,000 shares of Common Stock and $78,693 was paid on
     September 29, 1998 with respect to an additional 10,000,000 shares.
     Accordingly, pursuant to Instruction E of Form S-8, the registration fee is
     being paid with respect to the additional securities only.

(2)  Pursuant to Rule 416(a), this Registration Statement also covers such
     indeterminate number of additional shares of Common Stock as may be
     issuable by reason of the antidilution provisions of the Incentive Plan in
     the event of stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of determining the registration fee
     pursuant to Rule 457(h) and based on the average of the high and low prices
     of the Common Stock on the New York Stock Exchange - Composite Tape on May
     12, 2000 as reported in The Wall Street Journal.

(4)  Includes related stock purchase rights under the Registrant's rights
     agreement.

<PAGE>   2

                                  INTRODUCTION

     On August 12, 1991, Masco Corporation (the "Company" or "Registrant") filed
Registration Statement No. 33-42229 on Form S-8, registering 16,000,000 shares
of Company common stock, par value $1.00, as adjusted for a 100% stock split on
July 10, 1998, (the "Common Stock"), for issuance under the Masco Corporation
1991 Long Term Stock Incentive Plan (the "Plan"). On September 29, 1998, the
Registrant filed Registration Statement No. 333-64573 registering an additional
10,000,000 shares of Common Stock for issuance under the Plan. By this
Registration Statement, the Registrant increases the number of shares registered
under the Plan to 46,000,000. The contents of Registration Statements Nos.
33-42229 and 333-64573 are incorporated herein by reference.

ITEM 8. EXHIBITS.

EXHIBIT NO.                                 DESCRIPTION

4.a               Restated Certificate of Incorporation of the Company and
                  amendments thereto. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the
                  quarter ended June 30, 1998.)

4.b               Bylaws of the Company, as amended. (Incorporated by reference
                  to the Exhibits filed with the Company's Annual Report on Form
                  10-K for the year ended December 31, 1998.)

4.c               Rights Agreement dated as of December 6, 1995, between Masco
                  Corporation and The Bank of New York, as Rights Agent.
                  (Incorporated by reference to the Exhibits filed with the
                  Company's Annual Report on Form 10-K for the year ended
                  December 31, 1995) and Amendment No. 1 to Rights Agreement
                  dated as of September 23, 1998. (Incorporated by reference to
                  the Exhibits filed with the Company's Quarterly Report on Form
                  10-Q for the quarter ended September 30, 1998.)

*5                Opinion of John R. Leekley.

*23.a             Consent of PricewaterhouseCoopers LLP relating to the
                  financial statements and financial statement schedule of
                  the Company.

*23.b             Consent of PricewaterhouseCoopers LLP relating to the
                  financial  statements  and  financial statement schedule of
                  MascoTech, Inc.

*23.c             Consent of John R. Leekley, which is included as part of
                  Exhibit 5.

*24               Power of Attorney, included on the Signatures page of this
                  Registration Statement on Form S-8.


                                       2

<PAGE>   3




99.a              Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated July 10, 1998). (Incorporated by reference to the
                  Exhibits filed with the Company's Annual Report on Form 10-K
                  for the year ended December 31, 1999.)

*99.b             Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated May 17, 2000).
---------------
*Filed herewith.


                                       3

<PAGE>   4

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Company
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 Taylor and the State of Michigan on this 18th day of
May, 2000.

                                   MASCO CORPORATION


                                   By /s/ Richard A. Manoogian
                                      ---------------------------
                                      Richard A. Manoogian
                                      Chairman of the Board and
                                      Chief Executive Officer


                                POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Richard A. Manoogian and Eugene A. Gargaro, Jr.,
and each of them, his or her true and lawful attorneys-in-fact and agents, each
with full power of substitution and resubstitution, for him or her and in his or
her name, place and stead, in any and all capacities, to sign any and all
amendments (including post-effective amendments) to this Registration Statement,
and to file the same, with all exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission, granting unto
said attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done,
as fully to all intents and purposes as he or she might or would do in person,
hereby ratifying and confirming all that said attorneys-in-fact and agents or
any of them or his or their substitute or substitutes may lawfully 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 date indicated.


<TABLE>
<CAPTION>

     SIGNATURE                                              TITLE                             DATE
<S>                                                      <C>                                 <C>
PRINCIPAL EXECUTIVE OFFICER:

/s/  Richard A. Manoogian                                Chairman of the Board               May 18, 2000
-------------------------------------                    and Chief Executive Officer
     Richard A. Manoogian

PRINCIPAL FINANCIAL OFFICER:

/s/  Richard G. Mosteller                                Senior Vice President- Finance      May 18, 2000
-------------------------------------
     Richard G. Mosteller

</TABLE>


                                       4

<PAGE>   5





<TABLE>

<S>                                               <C>                                  <C>
PRINCIPAL ACCOUNTING OFFICER:

/s/   Robert B. Rosowski                          Vice President- Controller           May 18, 2000
------------------------                          and Treasurer
      Robert B. Rosowski

/s/   Raymond F. Kennedy                          President and Chief                  May 18, 2000
------------------------------                    Operating Officer and Director
      Raymond F. Kennedy


/s/   Thomas G. Denomme                           Director                             May 18, 2000
------------------------------
      Thomas G. Denomme


/s/   Joseph L. Hudson, Jr.                       Director                             May 18, 2000
------------------------------
      Joseph L. Hudson, Jr.


/s/   Verne G. Istock                             Director                             May 18, 2000
------------------------------
      Verne G. Istock


/s/   Mary Ann Krey                               Director                             May 18, 2000
------------------------------
      Mary Ann Krey


/s/   Wayne B. Lyon                               Director                             May 18, 2000
------------------------------
      Wayne B. Lyon


/s/   John A. Morgan                              Director                             May 18, 2000
------------------------------
      John A. Morgan


/s/   Arman Simone                                Director                             May 18, 2000
------------------------------
      Arman Simone


/s/   Peter W. Stroh                              Director                             May 18, 2000
------------------------------
      Peter W. Stroh

</TABLE>

                                       5

<PAGE>   6


                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>
                                                                                                       SEQUENTIALLY
EXHIBIT                                                                                                  NUMBERED
NO.                               DESCRIPTION                                                              PAGE

<S>               <C>                                                                                  <C>
4.a               Restated Certificate of Incorporation of the Company and
                  amendments thereto. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the
                  quarter ended June 30, 1998.)

4.b               Bylaws of the Company, as amended. (Incorporated by reference
                  to the Exhibits filed with the Company's Annual Report on Form
                  10-K for the year ended December 31, 1998.)

4.c               Rights Agreement dated as of December 6, 1995, between Masco Corporation
                  and The Bank of New York, as Rights Agent. (Incorporated by reference to
                  the Exhibits filed with the Company's Annual Report on Form 10-K for the
                  year ended December 31, 1995) and Amendment No. 1 to Rights Agreement
                  dated as of September 23, 1998. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1998.)

*5                Opinion of John R. Leekley.

*23.a             Consent of  PricewaterhouseCoopers  LLP relating to the financial  statements
                  and financial statement schedule of the Company.

*23.b             Consent of  PricewaterhouseCoopers  LLP relating to the financial  statements
                  and financial statement schedule of MascoTech, Inc.

*23.c             Consent of John R. Leekley, which is included as part of Exhibit 5.

*24               Power of  Attorney,  included  on the  Signatures  page of this  Registration
                  Statement on Form S-8.

99.a              Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated July 10, 1998). (Incorporated by reference to the
                  Exhibits filed with the Company's Annual Report on Form 10-K
                  for the year ended December 31, 1999.)

*99.b             Masco Corporation 1991 Long Term Stock Incentive Plan (amended and
                  restated May 17, 2000).
</TABLE>
---------------
*Filed herewith.


                                       6
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 14662}]
{"company-data": {"conformed-name": "MASCO CORP /DE/", "cik": "0000062996", "assigned-sic": "3430", "irs-number": "381794485", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-37338", "film-number": "639676"}, "business-address": {"street1": "21001 VAN BORN RD", "city": "TAYLOR", "state": "MI", "zip": "48180", "phone": "3132747400"}, "mail-address": {"street1": "21001 VAN BORN ROAD", "city": "TAYLOR", "state": "MI", "zip": "48180"}, "former-company": {"former-conformed-name": "MASCO SCREW PRODUCTS CO", "date-changed": "19731025"}}
1

AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 18, 2000.
                                                   REGISTRATION NO. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
             Registration Statement Under the Securities Act of 1933

                                MASCO CORPORATION
             (Exact Name of Registrant as Specified in its Charter)

         Delaware                                          38-1794485
(State or other jurisdiction of                          (IRS Employer
  incorporation)                                       Identification No.)

                   21001 Van Born Road, Taylor, Michigan 48180
               (Address of Principal Executive Offices) (Zip Code)

              MASCO CORPORATION 1991 LONG TERM STOCK INCENTIVE PLAN
                            (Full Title of the Plan)

                                 JOHN R. LEEKLEY
                    SENIOR VICE PRESIDENT AND GENERAL COUNSEL
                                MASCO CORPORATION
                               21001 VAN BORN ROAD
                             TAYLOR, MICHIGAN 48180
                     (Name and Address of Agent for Service)

                                 (313) 274-7400
           (Telephone no., including area code, of agent for service)

  If any of the securities being registered on this Form are to be offered on a
  delayed or continuous basis pursuant to Rule 415 under the Securities Act of
                       1933, check the following box. [X]

                         CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
            Title of                   Amount to          Proposed Maximum           Proposed Maximum
        Securities to be                   Be               Offering Price               Aggregate                 Amount of
           Registered               Registered(1)(2)         Per Share(3)            Offering Price(3)        Registration Fee(3)
-----------------------------------------------------------------------------------------------------------------------------------
Common Stock (Par Value $1.00
         Per Share) (4)                20,000,000              $20.65625                $413,125,000              $125,189.00
-----------------------------------------------------------------------------------------------------------------------------------
(1)  This Registration Statement registers additional shares of the Registrant's
     common stock issuable pursuant to the same plan for which Registration
     Statements No. 33-42229 and 333-64573 are currently effective. A
     registration fee of $45,250 paid on August 9, 1991 with the original filing
     to register 16,000,000 shares of Common Stock and $78,693 was paid on
     September 29, 1998 with respect to an additional 10,000,000 shares.
     Accordingly, pursuant to Instruction E of Form S-8, the registration fee is
     being paid with respect to the additional securities only.

(2)  Pursuant to Rule 416(a), this Registration Statement also covers such
     indeterminate number of additional shares of Common Stock as may be
     issuable by reason of the antidilution provisions of the Incentive Plan in
     the event of stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of determining the registration fee
     pursuant to Rule 457(h) and based on the average of the high and low prices
     of the Common Stock on the New York Stock Exchange - Composite Tape on May
     12, 2000 as reported in The Wall Street Journal.

(4)  Includes related stock purchase rights under the Registrant's rights
     agreement.
2

                                  INTRODUCTION

     On August 12, 1991, Masco Corporation (the "Company" or "Registrant") filed
Registration Statement No. 33-42229 on Form S-8, registering 16,000,000 shares
of Company common stock, par value $1.00, as adjusted for a 100% stock split on
July 10, 1998, (the "Common Stock"), for issuance under the Masco Corporation
1991 Long Term Stock Incentive Plan (the "Plan"). On September 29, 1998, the
Registrant filed Registration Statement No. 333-64573 registering an additional
10,000,000 shares of Common Stock for issuance under the Plan. By this
Registration Statement, the Registrant increases the number of shares registered
under the Plan to 46,000,000. The contents of Registration Statements Nos.
33-42229 and 333-64573 are incorporated herein by reference.

ITEM 8. EXHIBITS.

EXHIBIT NO.                                 DESCRIPTION

4.a               Restated Certificate of Incorporation of the Company and
                  amendments thereto. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the
                  quarter ended June 30, 1998.)

4.b               Bylaws of the Company, as amended. (Incorporated by reference
                  to the Exhibits filed with the Company's Annual Report on Form
                  10-K for the year ended December 31, 1998.)

4.c               Rights Agreement dated as of December 6, 1995, between Masco
                  Corporation and The Bank of New York, as Rights Agent.
                  (Incorporated by reference to the Exhibits filed with the
                  Company's Annual Report on Form 10-K for the year ended
                  December 31, 1995) and Amendment No. 1 to Rights Agreement
                  dated as of September 23, 1998. (Incorporated by reference to
                  the Exhibits filed with the Company's Quarterly Report on Form
                  10-Q for the quarter ended September 30, 1998.)

*5                Opinion of John R. Leekley.

*23.a             Consent of PricewaterhouseCoopers LLP relating to the
                  financial statements and financial statement schedule of
                  the Company.

*23.b             Consent of PricewaterhouseCoopers LLP relating to the
                  financial  statements  and  financial statement schedule of
                  MascoTech, Inc.

*23.c             Consent of John R. Leekley, which is included as part of
                  Exhibit 5.

*24               Power of Attorney, included on the Signatures page of this
                  Registration Statement on Form S-8.

                                       2
3

99.a              Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated July 10, 1998). (Incorporated by reference to the
                  Exhibits filed with the Company's Annual Report on Form 10-K
                  for the year ended December 31, 1999.)

*99.b             Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated May 17, 2000).
---------------
*Filed herewith.

                                       3
4

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Company
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 Taylor and the State of Michigan on this 18th day of
May, 2000.

                                   MASCO CORPORATION

                                   By /s/ Richard A. Manoogian
                                      ---------------------------
                                      Richard A. Manoogian
                                      Chairman of the Board and
                                      Chief Executive Officer

                                POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Richard A. Manoogian and Eugene A. Gargaro, Jr.,
and each of them, his or her true and lawful attorneys-in-fact and agents, each
with full power of substitution and resubstitution, for him or her and in his or
her name, place and stead, in any and all capacities, to sign any and all
amendments (including post-effective amendments) to this Registration Statement,
and to file the same, with all exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission, granting unto
said attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done,
as fully to all intents and purposes as he or she might or would do in person,
hereby ratifying and confirming all that said attorneys-in-fact and agents or
any of them or his or their substitute or substitutes may lawfully 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 date indicated.
SIGNATURE                                              TITLE                             DATE
PRINCIPAL EXECUTIVE OFFICER:

/s/  Richard A. Manoogian                                Chairman of the Board               May 18, 2000
-------------------------------------                    and Chief Executive Officer
     Richard A. Manoogian

PRINCIPAL FINANCIAL OFFICER:

/s/  Richard G. Mosteller                                Senior Vice President- Finance      May 18, 2000
-------------------------------------
     Richard G. Mosteller
4
5
PRINCIPAL ACCOUNTING OFFICER:

/s/   Robert B. Rosowski                          Vice President- Controller           May 18, 2000
------------------------                          and Treasurer
      Robert B. Rosowski

/s/   Raymond F. Kennedy                          President and Chief                  May 18, 2000
------------------------------                    Operating Officer and Director
      Raymond F. Kennedy

/s/   Thomas G. Denomme                           Director                             May 18, 2000
------------------------------
      Thomas G. Denomme

/s/   Joseph L. Hudson, Jr.                       Director                             May 18, 2000
------------------------------
      Joseph L. Hudson, Jr.

/s/   Verne G. Istock                             Director                             May 18, 2000
------------------------------
      Verne G. Istock

/s/   Mary Ann Krey                               Director                             May 18, 2000
------------------------------
      Mary Ann Krey

/s/   Wayne B. Lyon                               Director                             May 18, 2000
------------------------------
      Wayne B. Lyon

/s/   John A. Morgan                              Director                             May 18, 2000
------------------------------
      John A. Morgan

/s/   Arman Simone                                Director                             May 18, 2000
------------------------------
      Arman Simone

/s/   Peter W. Stroh                              Director                             May 18, 2000
------------------------------
      Peter W. Stroh
5
6

                                INDEX TO EXHIBITS
SEQUENTIALLY
EXHIBIT                                                                                                  NUMBERED
NO.                               DESCRIPTION                                                              PAGE
4.a               Restated Certificate of Incorporation of the Company and
                  amendments thereto. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the
                  quarter ended June 30, 1998.)

4.b               Bylaws of the Company, as amended. (Incorporated by reference
                  to the Exhibits filed with the Company's Annual Report on Form
                  10-K for the year ended December 31, 1998.)

4.c               Rights Agreement dated as of December 6, 1995, between Masco Corporation
                  and The Bank of New York, as Rights Agent. (Incorporated by reference to
                  the Exhibits filed with the Company's Annual Report on Form 10-K for the
                  year ended December 31, 1995) and Amendment No. 1 to Rights Agreement
                  dated as of September 23, 1998. (Incorporated by reference to the Exhibits
                  filed with the Company's Quarterly Report on Form 10-Q for the quarter
                  ended September 30, 1998.)

*5                Opinion of John R. Leekley.

*23.a             Consent of  PricewaterhouseCoopers  LLP relating to the financial  statements
                  and financial statement schedule of the Company.

*23.b             Consent of  PricewaterhouseCoopers  LLP relating to the financial  statements
                  and financial statement schedule of MascoTech, Inc.

*23.c             Consent of John R. Leekley, which is included as part of Exhibit 5.

*24               Power of  Attorney,  included  on the  Signatures  page of this  Registration
                  Statement on Form S-8.

99.a              Masco Corporation 1991 Long Term Stock Incentive Plan (amended
                  and restated July 10, 1998). (Incorporated by reference to the
                  Exhibits filed with the Company's Annual Report on Form 10-K
                  for the year ended December 31, 1999.)

*99.b             Masco Corporation 1991 Long Term Stock Incentive Plan (amended and
                  restated May 17, 2000).
---------------
*Filed herewith.

                                       6