EXHIBIT 5.1
                                  LEGAL OPINION

Stewart & Stevenson Services, Inc.
Houston, Texas

As Senior Counsel of Stewart & Stevenson Services, Inc. (the "Company"), a Texas
corporation, I have participated in the preparation and adoption of the Stewart
& Stevenson Services, Inc. 1993 Nonofficer Employee Stock Option Plan (the
"Plan") and the preparation of a Registration Statement on Form S-8 (the
"Registration Statement") with respect to 138,750 shares (the "Shares") of
Common Stock, without par value, of the Company to be offered to nonofficer
employees of the Company pursuant to options granted pursuant to the Plan.

It is my opinion that the Shares have been duly authorized and that, when issued
upon the exercise of an option granted pursuant to the Plan, the Shares will be
validly issued, fully paid and nonassessable.


/s/ WILLIAM L. MOLL, JR.
William L. Moll, Jr.
Senior Counsel
January 19, 2001