EXHIBIT 5.1

                       [LETTERHEAD OF COOLEY GODWARD, LLP]

October 15, 2001

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by Wireless Facilities, Inc., a Delaware corporation (the
"Company"), of a Registration Statement on Form S-3 (the "Registration
Statement") with the Securities and Exchange Commission, covering the offering
of up to 1,638,838 shares of the Company's Common Stock, $.001 par value (the
"Shares"), for resale by the selling stockholder named therein (the "Selling
Stockholder").

In connection with this opinion, we have examined the Registration Statement and
related Prospectus, your Certificate of Incorporation and Bylaws, as amended,
and such other documents, records, certificates, memoranda and other instruments
as we deem necessary as a basis for this opinion. We have assumed the
genuineness and authenticity of all documents submitted to us as originals, the
conformity to originals of all documents submitted to us as copies thereof, the
accuracy, completeness and authenticity of certificates of public officials and
the due execution and delivery of all documents where due execution and delivery
are a prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the Shares are validly issued, fully paid and non-assessable.

We consent to the reference to our firm under the caption "Legal Matters" in the
Prospectus included in the Registration Statement and to the filing of this
opinion as an exhibit to the Registration Statement.

Very truly yours,

Cooley Godward LLP

/s/ Lance W. Bridges
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Lance W. Bridges