<PAGE>
Law Office
STRADLEY, RONON, STEVENS & YOUNG, LLP
30 Valley Stream Parkway
Malvern, Pennsylvania 19355-1481
(640) 640-5800
Direct Dial: (610) 640-5801
July 28, 2000
Board of Directors
DFA Investment Dimensions Group Inc.
1199 Ocean Avenue, 11th Floor
Santa Monica, CA 90401
Gentlemen:
We have examined the Articles of Incorporation ("Articles") of DFA
Investment Dimensions Group Inc. (the "Fund"), a corporation organized under
Maryland law, and its by-laws, both as amended to date, the registration
statement filed by the Fund under the Securities Act of 1933, as amended
("Registration Statement"), and such records of the corporate proceedings as we
deem material to this opinion.
As of the date hereof: (i) the Fund is authorized to issue an aggregate
of Six Billion (6,000,000,000) shares of common stock, of a par value of $0.01
per share; and (ii) in accordance with authority provided in the Articles, the
board of directors has allocated 100,000,000 of authorized, but unissued, shares
of common stock to each of the following four (4) classes, and authorized the
issuance of such shares as provided in the Registration Statement:
LD U.S. Large Company Portfolio
HD U.S. Large Company Portfolio
LD U.S. Marketwide Value Portfolio
HD U.S. Marketwide Value Portfolio
Based upon the above-described examination, it is our opinion that
provided the Fund remains a corporation in good standing under the laws of the
state of Maryland, the authorized but unissued shares of each class of stock
listed above, when issued for the consideration established by the board of
directors, as described in the Registration Statement, will be, under the law of
the state of Maryland, legally issued, fully-paid, non-assessable outstanding
shares of common stock of the Fund.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to reference therein to us as counsel who have
rendered this opinion.
Very truly yours,
STRADLEY, RONON, STEVENS & YOUNG, LLP
By: /s/ Stephen W. Kline
----------------------------------------
Stephen W. Kline
SWK/lrr
