<PAGE>   1
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 31, 2001
                                                  REGISTRATION NO. 333-

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

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                                   ----------

                                ADMINISTAFF, INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                              76-0479645
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

                          19001 CRESCENT SPRINGS DRIVE
                           KINGWOOD, TEXAS 77339-3802
              (Address of principal executive offices and zip code)

                                   ----------

                      ADMINISTAFF, INC. 2001 INCENTIVE PLAN
                            (Full title of the plan)

                                   ----------

                               JOHN H. SPURGIN, II
             VICE PRESIDENT OF LEGAL, GENERAL COUNSEL AND SECRETARY
                                ADMINISTAFF, INC.
                          19001 CRESCENT SPRINGS DRIVE
                           KINGWOOD, TEXAS 77339-3802
                                 (281) 358-8986
 (Name, address and telephone number, including area code, of agent for service)

                                    copy to:

                                  KELLY B. ROSE
                               BAKER BOTTS L.L.P.
                                  910 LOUISIANA
                              HOUSTON, TEXAS 77002
                                 (713) 229-1768

                                   ----------

                         CALCULATION OF REGISTRATION FEE

<Table>
<Caption>
==================================================================================================================================
                                                                                                      PROPOSED
                                                             AMOUNT         PROPOSED MAXIMUM          MAXIMUM          AMOUNT OF
                                                             TO BE         OFFERING PRICE PER   AGGREGATE OFFERING    REGISTRATION
         TITLE OF SECURITIES TO BE REGISTERED             REGISTERED(2)         SHARE(1)              PRICE(1)           FEE(3)
----------------------------------------------------------------------------------------------------------------------------------

<S>                                                      <C>                     <C>               <C>                 <C>
Common stock, par value $.01 per share(2)(3) ......      1,500,000 shares        $22.645           $33,967,500         $8,491.88
==================================================================================================================================
</Table>

(1)  Estimated solely for the purpose of calculating the registration fee
     pursuant to 457(h), based on the average of the high and low prices of the
     common stock of Administaff, Inc. reported on the New York Stock Exchange
     Composite Tape on July 30, 2001.

(2)  Pursuant to Rule 416 under the Securities Act of 1933, as amended, this
     Registration Statement shall also include such additional indeterminant
     number of shares of common stock as may become issuable under the
     Administaff, Inc. 2001 Incentive Plan as a result of stock splits, stock
     dividends or similar transactions.

(3)  Includes associated preferred stock purchase rights. No separate
     consideration is payable for the preferred stock purchase rights.
     Therefore, the registration fee for such securities is included in the
     registration fee for the common stock.

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

<PAGE>   2

                             INTRODUCTORY STATEMENT

     Administaff, Inc. (the "Registrant" or the "Company"; SEC File No. 1-13998)
is filing this Registration Statement on Form S-8 relating to its common stock,
par value $.01 per share, and associated rights to purchase its Series A Junior
Participating Preferred Stock, par value $0.01 per share (such common stock and
associated rights, collectively, the "Common Stock"), issuable pursuant to the
terms of the Administaff, Inc. 2001 Incentive Plan.

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     Note: The document(s) containing the employee benefit plan information
required by Item 1 of Form S-8 and the statement of availability of Registrant
information and any other information required by Item 2 of Form S-8 will be
sent or given to participants as specified by Rule 428 under the Securities Act
of 1933, as amended (the "Securities Act"). In accordance with Rule 428 and the
requirements of Part I of Form S-8, such documents are not being filed with the
Securities and Exchange Commission (the "Commission") either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424 under the Securities Act. The Registrant shall maintain a file of such
documents in accordance with the provisions of Rule 428. Upon request, the
Registrant shall furnish to the Commission or its staff a copy or copies of all
of the documents included in such file.

     There are also registered hereunder such additional indeterminate shares of
the Registrant's common stock as may be required as a result of stock splits,
stock dividends or similar transactions.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     This registration statement incorporates herein by reference the following
documents which have been filed with the Commission by the Company pursuant to
the Securities Exchange Act of 1934, as amended (the "Exchange Act"):

     1. The Company's Annual Report on Form 10-K for the fiscal year ended
December 31, 2000.

     2. The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 2001.

     3. The summary of the rights to purchase preferred stock and the
description of the Company's Series A Junior Participating Preferred Stock, par
value $0.01 per share, contained in the Company's Registration Statement on Form
8-A filed with the Commission on February 5, 1998 and as subsequently amended on
May 19, 1999 and August 9, 1999.

     4. The description of the Company's common stock, par value $0.01 per
share, contained in the Company's Registration Statement on Form 8-A filed with
the Commission on October 6, 1995.

     Each document filed with the Commission by the Company pursuant to Sections
13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this
Registration Statement and prior to the filing of a post-effective amendment to
this Registration Statement which indicates that all securities offered hereby
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 a part hereof from the date of filing such documents.

     Any statement contained in this Registration Statement, in an amendment
hereto or in a document incorporated by reference herein shall be deemed to be
modified or superseded for purposes of this Registration Statement to the extent
that a statement contained herein or in any subsequently filed amendment to this
Registration Statement or in any document that also is incorporated by reference
herein modifies or supersedes such statement.

                                       1
<PAGE>   3

Any statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Registration Statement.

ITEM 4. DESCRIPTION OF SECURITIES.

     Not Applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Not Applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

DELAWARE CODE

     The Company is incorporated under the laws of the State of Delaware.
Section 145 ("Section 145") of Title 8 of the Delaware Code gives a corporation
power to 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 (other than an action
by or in the right of the corporation) by reason of the fact that the person is
or was a director, officer, employee or agent of the corporation, or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by the person in
connection with such action, suit or proceeding if the person acted in good
faith and in a manner the person reasonably believed to be in or not opposed to
the best interests of the corporation, and, with respect to any criminal action
or proceeding, had no reasonable cause to believe the person's conduct was
unlawful.

     Section 145 also gives a corporation power to indemnify any person who was
or is a party or is threatened to be made a party to any threatened, pending or
completed action or suit by or in the right of the corporation to procure a
judgment in its favor by reason of the fact that the person is or was a
director, officer, employee or agent of the corporation, or is or was serving at
the request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise
against expenses (including attorneys' fees) actually and reasonably incurred by
the person in connection with the defense or settlement of such action or suit
if the person acted in good faith and in a manner the person reasonably believed
to be in or not opposed to the best interests of the corporation and except that
no indemnification shall be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Delaware Court of Chancery or the court
in which such action or suit was brought shall determine upon application that,
despite the adjudication of liability but in view of all the circumstances of
the case, such person is fairly and reasonably entitled to indemnity for such
expenses which the Delaware Court of Chancery or such other court shall deem
proper. Section 145 further provides that, to the extent that a present or
former director or officer of a corporation has been successful on the merits or
otherwise in defense of any such action, suit or proceeding, or in defense of
any claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred by such
person in connection therewith.

     Section 145 provides that expenses (including attorneys' fees) incurred by
an officer or director in defending any civil, criminal, administrative or
investigative action, suit or proceeding may be paid by the corporation in
advance of the final disposition of such action, suit or proceeding upon receipt
of an undertaking by or on behalf of such director or officer to repay such
amount if it is ultimately determined that such person is not entitled to be
indemnified by the corporation as authorized by Section 145. Such expenses
(including attorneys' fees) incurred by former directors and officers or other
employees and agents may be so paid upon such terms and conditions, if any, as
the corporation deems appropriate.

                                       2
<PAGE>   4

     Section 145 also authorizes a corporation to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director, officer, employee or agent of another corporation, partnership,
joint venture, trust or other enterprise, against any liability asserted against
such person and incurred by such person in any such capacity, arising out of
such person's status as such, whether or not the corporation would otherwise
have the power to indemnify such person against such liability under Section
145.

     The above discussion of Section 145 is not intended to be exhaustive and is
qualified in its entirety by such statute.

AMENDED BYLAWS

     The Company's Amended Bylaws (the "Bylaws") provide for the indemnification
of its officers, directors, employees and agents and the advancement to them of
expenses in connection with actions, suits or proceedings, to the fullest extent
permitted by law. The indemnification and advancement of expenses provided by
the Company's Bylaws is not exclusive of any other rights to which those seeking
indemnification or advancement of expenses may be or become entitled under any
law, the Company's Certificate of Incorporation, the Company's Bylaws,
agreement, the vote of stockholders or disinterested directors or otherwise, or
under any policy or policies of insurance purchased and maintained by the
Company on behalf of any such person, both as to action in his official capacity
and as to action in another capacity while holding such office.

     The indemnification provided by the Company's Bylaws is subject to all
valid and applicable laws, and, in the event the Company's Bylaws or any of the
provisions thereof or the indemnification contemplated thereby are found to be
inconsistent with or contrary to any such valid laws, the latter shall be deemed
to control and the Company's Bylaws shall be regarded as modified accordingly,
and, as so modified, to continue in full force and effect. The indemnification
and advancement of expenses provided by the Company's Bylaws continues as to any
person who has ceased to be a director, officer, employee or agent of the
Company and will inure to the benefit of the estate, executors, administrators,
heirs, legatees and devisees of any person entitled to indemnification under the
Company's Bylaws.

     The above discussion of the Company's Bylaws is not intended to be
exhaustive and is qualified in its entirety by the Bylaws.

INSURANCE

     All of the Company's directors and officers will be covered by insurance
policies maintained by the Company against certain liabilities for actions taken
in their capacities as such, including liabilities under the Securities Act of
1933, as amended.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

     Not Applicable.

ITEM 8. EXHIBITS.

     The following documents are filed as a part of this Registration Statement
or incorporated by reference herein:

  Exhibit
    No.                                 Description

    4.1     --     Certificate of Incorporation of the Company (incorporated by
                   reference to Exhibit 3.1 to the Company's Registration
                   Statement on Form S-1 (No. 33-96952)).

    4.2     --     Bylaws of the Company (incorporated by reference to Exhibit
                   3.2 to the Company's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 2000).

                                       3
<PAGE>   5

    4.3     --     Certificate of Designations of Series A Junior Participating
                   Preferred Stock of the Company dated February 4, 1998
                   (incorporated by reference to Exhibit 2 to the Company's Form
                   8-A filed on February 4, 1998).

    4.4     --     Specimen Common Stock Certificate (incorporated by reference
                   to Exhibit 4.1 to the Company's Registration Statement on
                   Form S-1 (No. 33-96952)).

    4.5     --     Rights Agreement dated as of February 4, 1998, between the
                   Company and Harris Trust and Savings Bank, as Rights Agent
                   (incorporated by reference to Exhibit 1 to the Company's Form
                   8-A filed on February 4, 1998).

    4.6     --     Amendment No. 1 to Rights Agreement dated as of March 9, 1998
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 4.3 to the
                   Company's Form 10-K for the year ended December 31, 1999).

    4.7     --     Amendment No. 2 to Rights Agreement dated as of May 14, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 2 to the
                   Company's Form 8-A/A filed on May 19, 1999).

    4.8     --     Amendment No. 3 to Rights Agreement dated as of July 22, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 1 to the
                   Company's Form 8-A/A filed on August 9, 1999).

    4.9     --     Amendment No. 4 to Rights Agreement dated as of August 2,
                   1999 between the Company and Harris Trust and Savings Bank,
                   as Rights Agent (incorporated by reference to Exhibit 2 to
                   the Company's Form 8-A/A filed on August 9, 1999).

   4.10     --     Form of Rights Certificate (incorporated by reference to
                   Exhibit 3 to the Company's Form 8-A filed on February 4,
                   1998).

   4.11     --     Administaff, Inc. 2001 Incentive Plan (incorporated by
                   reference to Exhibit 10.3 to the Company's Form 10-Q for the
                   quarter ended March 31, 2001).

    5.1     --     Opinion of Baker Botts L.L.P.

   23.1     --     Consent of Ernst & Young LLP.

   23.2     --     Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

   24.1     --     Powers of Attorney (included on signature page to this
                   registration statement).

ITEM 9. UNDERTAKINGS.

     (a) The Company hereby undertakes:

          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
          Securities Act of 1933;

               (ii) To reflect in the prospectus any facts or events arising
          after the effective date of this registration statement (or the most
          recent post-effective amendment thereof) which, individually or in the
          aggregate, represent a fundamental change in the information set forth
          in the registration statement. Notwithstanding the foregoing, any
          increase or decrease in volume of securities offered (if the total
          dollar value of securities offered would not exceed that which was
          registered) and any deviation from the low or high end of the
          estimated maximum offering range may be reflected in the form of
          prospectus filed with the Commission pursuant to Rule 424(b) of the
          Securities Act of 1933 if, in the aggregate, the changes in volume and
          price represent no more than a 20% change in the maximum aggregate
          offering price set forth in the "Calculation of Registration Fee"
          table in the effective registration statement;

                                       4
<PAGE>   6

               (iii) To include any material information with respect to the
          plan of distribution not previously disclosed in this registration
          statement or any material change to such information in this
          registration statement;

     provided, however, that the undertakings set forth in paragraphs (a)(1)(i)
     and (a)(1)(ii) above do not apply if the registration statement is on Form
     S-3 or Form S-8 and the information required to be included in a
     post-effective amendment by those paragraphs is contained in periodic
     reports filed by the registrant pursuant to Section 13 or Section 15(d) of
     the Securities Exchange Act of 1934 that are incorporated by reference in
     this registration statement.

          (2) That, for the purpose of determining any liability under the
     Securities Act of 1933, 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
     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 of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
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 of 1933 may be permitted to directors, officers and controlling persons of
the registrant pursuant to the provisions described under Item 6 above, 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
of 1933 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 of whether such
indemnification by it is against public policy as expressed in the Securities
Act of 1933 and will be governed by the final adjudication of such issue.

                                       5
<PAGE>   7

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
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 Houston, State of Texas, on July 31, 2001.

                                  ADMINISTAFF, INC.


                                  By: /s/ Richard G. Rawson
                                      -----------------------------------------
                                      Richard G. Rawson
                                      Executive Vice President, Administration,
                                      Chief Financial Officer and Treasurer

                                POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Paul J. Sarvadi and Richard G. Rawson, and each
of them severally, his or her true and lawful attorney or attorneys-in-fact and
agents, with full power to act with or without the others and with full power of
substitution and resubstitution, to execute in his or her name place and stead,
in any and all capacities, any or all amendments (including post-effective
amendments) to this Registration Statement under the Securities Act of 1933, as
amended, 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 in the name and on behalf of the undersigned, in any and all
capacities, each and every act and thing necessary or desirable to be done in
and about the premises, to all intents and purposes and as fully as they might
or could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents or their 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 indicated and on July 31, 2001.

<Table>
<S>                                            <C>    <C>    <C>    <C>    <C>    <C>
      /s/ Paul J. Sarvadi                   President, Chief Executive Officer and Director (Principal
-----------------------------------         Executive Officer)
      Paul J. Sarvadi

      /s/ Richard G. Rawson                 Executive Vice President, Administration,
-----------------------------------         Chief Financial Officer, Treasurer and Director
      Richard G. Rawson                     (Principal Financial Officer)

  /s/ Douglas S. Sharp                      Vice President, Finance and Controller (Principal
-----------------------------------         Accounting Officer)
      Douglas S. Sharp

  /s/ Jack M. Fields, Jr.                   Director
-----------------------------------
      Jack M. Fields, Jr.

      /s/ Paul S. Lattanzio                 Director
-----------------------------------
      Paul S. Lattanzio

  /s/ Linda Fayne Levinson                  Director
-----------------------------------
      Linda Fayne Levinson

      /s/ Steven Alesio                     Director
-----------------------------------
      Steven Alesio

                                            Director
-----------------------------------
      Michael W. Brown
</Table>

                                       6
<PAGE>   8

                                  EXHIBIT INDEX

<Table>
<Caption>
  Exhibit
    No.                           DESCRIPTION
  -------                         -----------

<S>                <C>
    4.1     --     Certificate of Incorporation of the Company (incorporated by
                   reference to Exhibit 3.1 to the Company's Registration
                   Statement on Form S-1 (No. 33-96952)).

    4.2     --     Bylaws of the Company (incorporated by reference to Exhibit
                   3.2 to the Company's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 2000).

    4.3     --     Certificate of Designations of Series A Junior Participating
                   Preferred Stock of the Company dated February 4, 1998
                   (incorporated by reference to Exhibit 2 to the Company's Form
                   8-A filed on February 4, 1998).

    4.4     --     Specimen Common Stock Certificate (incorporated by reference
                   to Exhibit 4.1 to the Company's Registration Statement on
                   Form S-1 (No. 33-96952)).

    4.5     --     Rights Agreement dated as of February 4, 1998, between the
                   Company and Harris Trust and Savings Bank, as Rights Agent
                   (incorporated by reference to Exhibit 1 to the Company's Form
                   8-A filed on February 4, 1998).

    4.6     --     Amendment No. 1 to Rights Agreement dated as of March 9, 1998
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 4.3 to the
                   Company's Form 10-K for the year ended December 31, 1999).

    4.7     --     Amendment No. 2 to Rights Agreement dated as of May 14, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 2 to the
                   Company's Form 8-A/A filed on May 19, 1999).

    4.8     --     Amendment No. 3 to Rights Agreement dated as of July 22, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 1 to the
                   Company's Form 8-A/A filed on August 9, 1999).

    4.9     --     Amendment No. 4 to Rights Agreement dated as of August 2,
                   1999 between the Company and Harris Trust and Savings Bank,
                   as Rights Agent (incorporated by reference to Exhibit 2 to
                   the Company's Form 8-A/A filed on August 9, 1999).

   4.10     --     Form of Rights Certificate (incorporated by reference to
                   Exhibit 3 to the Company's Form 8-A filed on February 4,
                   1998).

   4.11     --     Administaff, Inc. 2001 Incentive Plan (incorporated by
                   reference to Exhibit 10.3 to the Company's Form 10-Q for the
                   quarter ended March 31, 2001).

    5.1     --     Opinion of Baker Botts L.L.P.

   23.1     --     Consent of Ernst & Young LLP.

   23.2     --     Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

   24.1     --     Powers of Attorney (included on signature page to this
                   registration statement).
</Table>

                                       7
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1
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 31, 2001
                                                  REGISTRATION NO. 333-

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

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                                   ----------

                                ADMINISTAFF, INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                              76-0479645
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

                          19001 CRESCENT SPRINGS DRIVE
                           KINGWOOD, TEXAS 77339-3802
              (Address of principal executive offices and zip code)

                                   ----------

                      ADMINISTAFF, INC. 2001 INCENTIVE PLAN
                            (Full title of the plan)

                                   ----------

                               JOHN H. SPURGIN, II
             VICE PRESIDENT OF LEGAL, GENERAL COUNSEL AND SECRETARY
                                ADMINISTAFF, INC.
                          19001 CRESCENT SPRINGS DRIVE
                           KINGWOOD, TEXAS 77339-3802
                                 (281) 358-8986
 (Name, address and telephone number, including area code, of agent for service)

                                    copy to:

                                  KELLY B. ROSE
                               BAKER BOTTS L.L.P.
                                  910 LOUISIANA
                              HOUSTON, TEXAS 77002
                                 (713) 229-1768

                                   ----------

                         CALCULATION OF REGISTRATION FEE
==================================================================================================================================
                                                                                                      PROPOSED
                                                             AMOUNT         PROPOSED MAXIMUM          MAXIMUM          AMOUNT OF
                                                             TO BE         OFFERING PRICE PER   AGGREGATE OFFERING    REGISTRATION
         TITLE OF SECURITIES TO BE REGISTERED             REGISTERED(2)         SHARE(1)              PRICE(1)           FEE(3)
----------------------------------------------------------------------------------------------------------------------------------
Common stock, par value $.01 per share(2)(3) ......      1,500,000 shares        $22.645           $33,967,500         $8,491.88
==================================================================================================================================
(1)  Estimated solely for the purpose of calculating the registration fee
     pursuant to 457(h), based on the average of the high and low prices of the
     common stock of Administaff, Inc. reported on the New York Stock Exchange
     Composite Tape on July 30, 2001.

(2)  Pursuant to Rule 416 under the Securities Act of 1933, as amended, this
     Registration Statement shall also include such additional indeterminant
     number of shares of common stock as may become issuable under the
     Administaff, Inc. 2001 Incentive Plan as a result of stock splits, stock
     dividends or similar transactions.

(3)  Includes associated preferred stock purchase rights. No separate
     consideration is payable for the preferred stock purchase rights.
     Therefore, the registration fee for such securities is included in the
     registration fee for the common stock.

================================================================================
2

                             INTRODUCTORY STATEMENT

     Administaff, Inc. (the "Registrant" or the "Company"; SEC File No. 1-13998)
is filing this Registration Statement on Form S-8 relating to its common stock,
par value $.01 per share, and associated rights to purchase its Series A Junior
Participating Preferred Stock, par value $0.01 per share (such common stock and
associated rights, collectively, the "Common Stock"), issuable pursuant to the
terms of the Administaff, Inc. 2001 Incentive Plan.

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     Note: The document(s) containing the employee benefit plan information
required by Item 1 of Form S-8 and the statement of availability of Registrant
information and any other information required by Item 2 of Form S-8 will be
sent or given to participants as specified by Rule 428 under the Securities Act
of 1933, as amended (the "Securities Act"). In accordance with Rule 428 and the
requirements of Part I of Form S-8, such documents are not being filed with the
Securities and Exchange Commission (the "Commission") either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424 under the Securities Act. The Registrant shall maintain a file of such
documents in accordance with the provisions of Rule 428. Upon request, the
Registrant shall furnish to the Commission or its staff a copy or copies of all
of the documents included in such file.

     There are also registered hereunder such additional indeterminate shares of
the Registrant's common stock as may be required as a result of stock splits,
stock dividends or similar transactions.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     This registration statement incorporates herein by reference the following
documents which have been filed with the Commission by the Company pursuant to
the Securities Exchange Act of 1934, as amended (the "Exchange Act"):

     1. The Company's Annual Report on Form 10-K for the fiscal year ended
December 31, 2000.

     2. The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 2001.

     3. The summary of the rights to purchase preferred stock and the
description of the Company's Series A Junior Participating Preferred Stock, par
value $0.01 per share, contained in the Company's Registration Statement on Form
8-A filed with the Commission on February 5, 1998 and as subsequently amended on
May 19, 1999 and August 9, 1999.

     4. The description of the Company's common stock, par value $0.01 per
share, contained in the Company's Registration Statement on Form 8-A filed with
the Commission on October 6, 1995.

     Each document filed with the Commission by the Company pursuant to Sections
13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this
Registration Statement and prior to the filing of a post-effective amendment to
this Registration Statement which indicates that all securities offered hereby
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 a part hereof from the date of filing such documents.

     Any statement contained in this Registration Statement, in an amendment
hereto or in a document incorporated by reference herein shall be deemed to be
modified or superseded for purposes of this Registration Statement to the extent
that a statement contained herein or in any subsequently filed amendment to this
Registration Statement or in any document that also is incorporated by reference
herein modifies or supersedes such statement.

                                       1
3

Any statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Registration Statement.

ITEM 4. DESCRIPTION OF SECURITIES.

     Not Applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Not Applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

DELAWARE CODE

     The Company is incorporated under the laws of the State of Delaware.
Section 145 ("Section 145") of Title 8 of the Delaware Code gives a corporation
power to 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 (other than an action
by or in the right of the corporation) by reason of the fact that the person is
or was a director, officer, employee or agent of the corporation, or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by the person in
connection with such action, suit or proceeding if the person acted in good
faith and in a manner the person reasonably believed to be in or not opposed to
the best interests of the corporation, and, with respect to any criminal action
or proceeding, had no reasonable cause to believe the person's conduct was
unlawful.

     Section 145 also gives a corporation power to indemnify any person who was
or is a party or is threatened to be made a party to any threatened, pending or
completed action or suit by or in the right of the corporation to procure a
judgment in its favor by reason of the fact that the person is or was a
director, officer, employee or agent of the corporation, or is or was serving at
the request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise
against expenses (including attorneys' fees) actually and reasonably incurred by
the person in connection with the defense or settlement of such action or suit
if the person acted in good faith and in a manner the person reasonably believed
to be in or not opposed to the best interests of the corporation and except that
no indemnification shall be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Delaware Court of Chancery or the court
in which such action or suit was brought shall determine upon application that,
despite the adjudication of liability but in view of all the circumstances of
the case, such person is fairly and reasonably entitled to indemnity for such
expenses which the Delaware Court of Chancery or such other court shall deem
proper. Section 145 further provides that, to the extent that a present or
former director or officer of a corporation has been successful on the merits or
otherwise in defense of any such action, suit or proceeding, or in defense of
any claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred by such
person in connection therewith.

     Section 145 provides that expenses (including attorneys' fees) incurred by
an officer or director in defending any civil, criminal, administrative or
investigative action, suit or proceeding may be paid by the corporation in
advance of the final disposition of such action, suit or proceeding upon receipt
of an undertaking by or on behalf of such director or officer to repay such
amount if it is ultimately determined that such person is not entitled to be
indemnified by the corporation as authorized by Section 145. Such expenses
(including attorneys' fees) incurred by former directors and officers or other
employees and agents may be so paid upon such terms and conditions, if any, as
the corporation deems appropriate.

                                       2
4

     Section 145 also authorizes a corporation to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director, officer, employee or agent of another corporation, partnership,
joint venture, trust or other enterprise, against any liability asserted against
such person and incurred by such person in any such capacity, arising out of
such person's status as such, whether or not the corporation would otherwise
have the power to indemnify such person against such liability under Section
145.

     The above discussion of Section 145 is not intended to be exhaustive and is
qualified in its entirety by such statute.

AMENDED BYLAWS

     The Company's Amended Bylaws (the "Bylaws") provide for the indemnification
of its officers, directors, employees and agents and the advancement to them of
expenses in connection with actions, suits or proceedings, to the fullest extent
permitted by law. The indemnification and advancement of expenses provided by
the Company's Bylaws is not exclusive of any other rights to which those seeking
indemnification or advancement of expenses may be or become entitled under any
law, the Company's Certificate of Incorporation, the Company's Bylaws,
agreement, the vote of stockholders or disinterested directors or otherwise, or
under any policy or policies of insurance purchased and maintained by the
Company on behalf of any such person, both as to action in his official capacity
and as to action in another capacity while holding such office.

     The indemnification provided by the Company's Bylaws is subject to all
valid and applicable laws, and, in the event the Company's Bylaws or any of the
provisions thereof or the indemnification contemplated thereby are found to be
inconsistent with or contrary to any such valid laws, the latter shall be deemed
to control and the Company's Bylaws shall be regarded as modified accordingly,
and, as so modified, to continue in full force and effect. The indemnification
and advancement of expenses provided by the Company's Bylaws continues as to any
person who has ceased to be a director, officer, employee or agent of the
Company and will inure to the benefit of the estate, executors, administrators,
heirs, legatees and devisees of any person entitled to indemnification under the
Company's Bylaws.

     The above discussion of the Company's Bylaws is not intended to be
exhaustive and is qualified in its entirety by the Bylaws.

INSURANCE

     All of the Company's directors and officers will be covered by insurance
policies maintained by the Company against certain liabilities for actions taken
in their capacities as such, including liabilities under the Securities Act of
1933, as amended.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

     Not Applicable.

ITEM 8. EXHIBITS.

     The following documents are filed as a part of this Registration Statement
or incorporated by reference herein:

  Exhibit
    No.                                 Description

    4.1     --     Certificate of Incorporation of the Company (incorporated by
                   reference to Exhibit 3.1 to the Company's Registration
                   Statement on Form S-1 (No. 33-96952)).

    4.2     --     Bylaws of the Company (incorporated by reference to Exhibit
                   3.2 to the Company's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 2000).

                                       3
5

    4.3     --     Certificate of Designations of Series A Junior Participating
                   Preferred Stock of the Company dated February 4, 1998
                   (incorporated by reference to Exhibit 2 to the Company's Form
                   8-A filed on February 4, 1998).

    4.4     --     Specimen Common Stock Certificate (incorporated by reference
                   to Exhibit 4.1 to the Company's Registration Statement on
                   Form S-1 (No. 33-96952)).

    4.5     --     Rights Agreement dated as of February 4, 1998, between the
                   Company and Harris Trust and Savings Bank, as Rights Agent
                   (incorporated by reference to Exhibit 1 to the Company's Form
                   8-A filed on February 4, 1998).

    4.6     --     Amendment No. 1 to Rights Agreement dated as of March 9, 1998
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 4.3 to the
                   Company's Form 10-K for the year ended December 31, 1999).

    4.7     --     Amendment No. 2 to Rights Agreement dated as of May 14, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 2 to the
                   Company's Form 8-A/A filed on May 19, 1999).

    4.8     --     Amendment No. 3 to Rights Agreement dated as of July 22, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 1 to the
                   Company's Form 8-A/A filed on August 9, 1999).

    4.9     --     Amendment No. 4 to Rights Agreement dated as of August 2,
                   1999 between the Company and Harris Trust and Savings Bank,
                   as Rights Agent (incorporated by reference to Exhibit 2 to
                   the Company's Form 8-A/A filed on August 9, 1999).

   4.10     --     Form of Rights Certificate (incorporated by reference to
                   Exhibit 3 to the Company's Form 8-A filed on February 4,
                   1998).

   4.11     --     Administaff, Inc. 2001 Incentive Plan (incorporated by
                   reference to Exhibit 10.3 to the Company's Form 10-Q for the
                   quarter ended March 31, 2001).

    5.1     --     Opinion of Baker Botts L.L.P.

   23.1     --     Consent of Ernst & Young LLP.

   23.2     --     Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

   24.1     --     Powers of Attorney (included on signature page to this
                   registration statement).

ITEM 9. UNDERTAKINGS.

     (a) The Company hereby undertakes:

          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
          Securities Act of 1933;

               (ii) To reflect in the prospectus any facts or events arising
          after the effective date of this registration statement (or the most
          recent post-effective amendment thereof) which, individually or in the
          aggregate, represent a fundamental change in the information set forth
          in the registration statement. Notwithstanding the foregoing, any
          increase or decrease in volume of securities offered (if the total
          dollar value of securities offered would not exceed that which was
          registered) and any deviation from the low or high end of the
          estimated maximum offering range may be reflected in the form of
          prospectus filed with the Commission pursuant to Rule 424(b) of the
          Securities Act of 1933 if, in the aggregate, the changes in volume and
          price represent no more than a 20% change in the maximum aggregate
          offering price set forth in the "Calculation of Registration Fee"
          table in the effective registration statement;

                                       4
6

               (iii) To include any material information with respect to the
          plan of distribution not previously disclosed in this registration
          statement or any material change to such information in this
          registration statement;

     provided, however, that the undertakings set forth in paragraphs (a)(1)(i)
     and (a)(1)(ii) above do not apply if the registration statement is on Form
     S-3 or Form S-8 and the information required to be included in a
     post-effective amendment by those paragraphs is contained in periodic
     reports filed by the registrant pursuant to Section 13 or Section 15(d) of
     the Securities Exchange Act of 1934 that are incorporated by reference in
     this registration statement.

          (2) That, for the purpose of determining any liability under the
     Securities Act of 1933, 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
     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 of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
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 of 1933 may be permitted to directors, officers and controlling persons of
the registrant pursuant to the provisions described under Item 6 above, 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
of 1933 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 of whether such
indemnification by it is against public policy as expressed in the Securities
Act of 1933 and will be governed by the final adjudication of such issue.

                                       5
7

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
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 Houston, State of Texas, on July 31, 2001.

                                  ADMINISTAFF, INC.

                                  By: /s/ Richard G. Rawson
                                      -----------------------------------------
                                      Richard G. Rawson
                                      Executive Vice President, Administration,
                                      Chief Financial Officer and Treasurer

                                POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Paul J. Sarvadi and Richard G. Rawson, and each
of them severally, his or her true and lawful attorney or attorneys-in-fact and
agents, with full power to act with or without the others and with full power of
substitution and resubstitution, to execute in his or her name place and stead,
in any and all capacities, any or all amendments (including post-effective
amendments) to this Registration Statement under the Securities Act of 1933, as
amended, 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 in the name and on behalf of the undersigned, in any and all
capacities, each and every act and thing necessary or desirable to be done in
and about the premises, to all intents and purposes and as fully as they might
or could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents or their 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 indicated and on July 31, 2001.
/s/ Paul J. Sarvadi                   President, Chief Executive Officer and Director (Principal
-----------------------------------         Executive Officer)
      Paul J. Sarvadi

      /s/ Richard G. Rawson                 Executive Vice President, Administration,
-----------------------------------         Chief Financial Officer, Treasurer and Director
      Richard G. Rawson                     (Principal Financial Officer)

  /s/ Douglas S. Sharp                      Vice President, Finance and Controller (Principal
-----------------------------------         Accounting Officer)
      Douglas S. Sharp

  /s/ Jack M. Fields, Jr.                   Director
-----------------------------------
      Jack M. Fields, Jr.

      /s/ Paul S. Lattanzio                 Director
-----------------------------------
      Paul S. Lattanzio

  /s/ Linda Fayne Levinson                  Director
-----------------------------------
      Linda Fayne Levinson

      /s/ Steven Alesio                     Director
-----------------------------------
      Steven Alesio

                                            Director
-----------------------------------
      Michael W. Brown
6
8

                                  EXHIBIT INDEX
Exhibit
    No.                           DESCRIPTION
  -------                         -----------
4.1     --     Certificate of Incorporation of the Company (incorporated by
                   reference to Exhibit 3.1 to the Company's Registration
                   Statement on Form S-1 (No. 33-96952)).

    4.2     --     Bylaws of the Company (incorporated by reference to Exhibit
                   3.2 to the Company's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 2000).

    4.3     --     Certificate of Designations of Series A Junior Participating
                   Preferred Stock of the Company dated February 4, 1998
                   (incorporated by reference to Exhibit 2 to the Company's Form
                   8-A filed on February 4, 1998).

    4.4     --     Specimen Common Stock Certificate (incorporated by reference
                   to Exhibit 4.1 to the Company's Registration Statement on
                   Form S-1 (No. 33-96952)).

    4.5     --     Rights Agreement dated as of February 4, 1998, between the
                   Company and Harris Trust and Savings Bank, as Rights Agent
                   (incorporated by reference to Exhibit 1 to the Company's Form
                   8-A filed on February 4, 1998).

    4.6     --     Amendment No. 1 to Rights Agreement dated as of March 9, 1998
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 4.3 to the
                   Company's Form 10-K for the year ended December 31, 1999).

    4.7     --     Amendment No. 2 to Rights Agreement dated as of May 14, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 2 to the
                   Company's Form 8-A/A filed on May 19, 1999).

    4.8     --     Amendment No. 3 to Rights Agreement dated as of July 22, 1999
                   between the Company and Harris Trust and Savings Bank, as
                   Rights Agent (incorporated by reference to Exhibit 1 to the
                   Company's Form 8-A/A filed on August 9, 1999).

    4.9     --     Amendment No. 4 to Rights Agreement dated as of August 2,
                   1999 between the Company and Harris Trust and Savings Bank,
                   as Rights Agent (incorporated by reference to Exhibit 2 to
                   the Company's Form 8-A/A filed on August 9, 1999).

   4.10     --     Form of Rights Certificate (incorporated by reference to
                   Exhibit 3 to the Company's Form 8-A filed on February 4,
                   1998).

   4.11     --     Administaff, Inc. 2001 Incentive Plan (incorporated by
                   reference to Exhibit 10.3 to the Company's Form 10-Q for the
                   quarter ended March 31, 2001).

    5.1     --     Opinion of Baker Botts L.L.P.

   23.1     --     Consent of Ernst & Young LLP.

   23.2     --     Consent of Baker Botts L.L.P. (included in Exhibit 5.1).

   24.1     --     Powers of Attorney (included on signature page to this
                   registration statement).
7