EXHIBIT 5.1









                                 January 7, 1998


Silicon Valley Group, Inc.
101 Metro Drive
San Jose, CA 95110

     Re:  220,372 Shares of Common Stock of Silicon Valley Group, Inc. Offered
     pursuant to stock plan and option agreements assumed in connection with
     the acquisition of Tinsley Laboratories, Inc.

Ladies and Gentlemen:

     We have examined the proceedings taken and the instruments executed in 
connection with the reservation for issuance and authorization of the sale 
and issuance from time to time by Silicon Valley Group, Inc. (the "Company") 
of not in excess of 220,372 shares of the Company's Common Stock (the 
"Shares") in connection with the acquisition of Tinsley Laboratories, Inc. 
("TLI") by the Company and the assumption by the Company of outstanding 
options to purchase TLI's Common Stock originally issued pursuant to TLI's 
1993 Incentive Stock Option Plan (the "Plan") and various Nonqualified Stock 
Option Agreements (the "Agreements").  The Shares are the subject of a 
Registration Statement on Form S-8 under the Securities Act of 1933, as 
amended, which is being filed with the Securities and Exchange Commission and 
to which this opinion is to be attached as an exhibit.

     It is our opinion that, upon completion of the actions being taken, or
contemplated by us as your counsel to be taken by you prior to the issuance of
the Shares pursuant to the Registration Statement and the Plan or the
Agreements, and upon completion of the actions being taken in order to permit
such transactions to be carried out in accordance with the securities laws of
the various states where required, the Shares will be legally and validly
issued, fully-paid and non-assessable.

     We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name wherever appearing in the
Registration Statement and any amendments thereto.

                              Very truly yours,

                              WILSON SONSINI GOODRICH & ROSATI
                              Professional Corporation

                              Wilson, Sonsini, Goodrich & Rosati