Exhibit 5.1



                                January 30, 2001





Actel Corporation
955 East Arques Avenue
Sunnyvale, California  94086

         Re:      Registration Statement on Form S-8

Ladies and Gentlemen:

         We have examined the Registration  Statement on Form S-8 to be filed by
you with the  Securities  and Exchange  Commission  on or about January 30, 2001
(the  "Registration  Statement"),  in connection with the registration under the
Securities Act of 1933, as amended,  of 172,070 shares of your Common Stock, par
value $0.01 per share (the  "Shares")  reserved for issuance under the GateField
Corporation  1993 Stock Option  Plan,  GateField  Corporation  1996 Stock Option
Plan, and the GateField Corporation 1999 Stock Option Plan. As legal counsel for
Actel Corporation,  a California  corporation,  we have examined the proceedings
taken  and are  familiar  with the  proceedings  proposed  to be taken by you in
connection with the issuance and sale of the Shares pursuant to the Plans.

         It is our opinion that, when issued and sold in the manner described in
the Plans and pursuant to the  agreements  which  accompany each grant under the
Plans,   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