OPINION OF AKIN GUMP STRAUSS HAUER & FELD

EXHIBIT 5.1
AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.
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June 21, 1999
Quanta Services, Inc.
1360 Post Oak Blvd., Suite 2100
Houston, Texas 77056

Ladies and Gentlemen:

We have acted as counsel to Quanta Services, Inc., a Delaware
corporation (the "COMPANY"), in connection with the Company's registration under
the Securities Act of 1933, as amended (the "ACT"), of 168,618 shares of common
stock, par value $0.00001 per share (the "SHARES"), of the Company which may be
offered from time to time under the Company's Registration Statement on Form S-3
(the "REGISTRATION STATEMENT") to be filed with the Securities and Exchange
Commission on or about June 22, 1999, by the stockholders named in such
Registration Statement (the "Selling Stockholders").

In reaching the opinions set forth herein, we have examined and are
familiar with originals or copies, certified or otherwise identified to our
satisfaction, of such documents and records of the Company and such statutes,
regulations and other instruments as we deemed necessary or advisable for
purposes of this opinion, including (i) the Registration Statement, (ii) the
Amended and Restated Certificate of Incorporation of the Company, as filed with
the Secretary of State of the State of Delaware, (iii) the Bylaws of the
Company, and (iv) certain minutes of meetings of, and resolutions adopted by,
the Board of Directors of the Company.

We have assumed that (i) all signatures on all documents we reviewed
are genuine, (ii) all documents submitted to us as originals are true and
complete, (iii) all documents submitted to us as copies are true and complete
copies of the originals thereof, and (iv) all persons executing and delivering
the documents we examined were competent to execute and deliver such documents.

Based on the foregoing, and having due regard for the legal
considerations we deem relevant, we are of the opinion that the Shares which are
to be sold and delivered by the Selling Stockholders, when delivered by the
Selling Stockholders, will be duly authorized, validly issued, fully paid and
non-assessable.

This opinion is limited in all respects to the laws of the State of
Texas, the Delaware General Corporation Law and the federal laws of the United
States of America.

This opinion letter may be filed as an exhibit to the Registration
Statement. In giving this consent, we do not thereby admit that we come within
the category of persons whose consent is required under Section 7 of the Act or
the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Akin, Gump, Strauss, Hauer & Feld L.L.P.

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