EXHIBIT NO. EX-99.h.2

                      DFA INVESTMENT DIMENSIONS GROUP INC.

                ADMINISTRATION AND ACCOUNTING SERVICES AGREEMENT
                              ADDENDUM NUMBER THREE

         THIS AGREEMENT is made as of this ___ day of July, 2000 by and
between DFA INVESTMENT DIMENSIONS GROUP INC., a Maryland corporation (the
"Fund"), and PFPC INC., formerly known as "Provident Financial Processing
Corporation," a Delaware corporation, ("PFPC").

                              W I T N E S S E T H :

         WHEREAS, the Fund is registered as an open-end, management
investment company under the Investment Company Act of 1940, as amended, and
its shares are registered under the Securities Act of 1933, as amended; and

         WHEREAS, the Fund has retained PFPC to provide certain
administration and accounting services pursuant to an Administration and
Accounting Services Agreement dated June 19, 1989, (the "Agreement") which,
as of the date hereof, remains in full force and effect; and

         WHEREAS, Paragraph 1 of the Agreement provides that PFPC shall
provide such services to any portfolio organized by the Fund after the date
of the Agreement as agreed to in writing by PFPC and the Fund; and

         WHEREAS, PFPC presently provides administration and accounting
services to the existing portfolios of the Fund, and has agreed to provide
such services to four (4) new portfolios of the Fund, designated as the LD
U.S. Large Company Portfolio, HD U.S. Large Company Portfolio, LD U.S.
Marketwide Value Portfolio and HD U.S. Marketwide Value Portfolio, which are
listed on Schedule A, attached hereto; and

         NOW, THEREFORE, in consideration of the premises and mutual
covenants herein contained, and intending to be legally bound, the parties
hereby agree that:

         1.   The Agreement is amended to provide that those portfolios set
forth on "Schedule A, Portfolios of the DFA Investment Dimensions Group Inc.,
Amended and Restated as of July __, 2000," which is attached hereto, shall be
"Portfolios" under the Agreement.



         2.   The fee schedules of PFPC applicable to the Portfolios shall be
as agreed to in writing, from time to time, by the Fund and PFPC.

         3.   In all other respects, the Agreement shall remain unchanged and
in full force and effect.

         4.   This Addendum may be executed in two or more counterparts, each
of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

         IN WITNESS WHEREOF, the parties hereto have caused this Addendum
Number Three to the Agreement to be executed by their duly authorized
officers designated below on the day and year first above written.

                                       DFA INVESTMENT DIMENSIONS GROUP INC.

                                       By:
                                           --------------------------------
                                           Catherine L. Newell
                                           Vice President


                                       PFPC INC.

                                       By:
                                           --------------------------------
                                           Joseph Gramlich
                                           Senior Vice President