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Fraser Milner Casgrain LLP   June 23, 2005
 Stantec Inc.
10160  112 Street
Edmonton, Alberta T5K 2L6
    Fraser Milner Casgrain LLP
2900 Manulife Place
10180 - 101 Street
Edmonton, AB T5J 3V5
Canada Dear Sirs/Mesdames:  Re:
    Stantec Inc.Registration Statement on Form F-4 (File No. 333-124748) We have acted as Canadian counsel to Stantec Inc., a corporation incorporated under the Canada
Business Corporations Act(the Company), in connection with the Registration Statement on Form
F-4 (the Registration Statement) (Registration No. 333-124748) filed by the Company with the
Securities and Exchange Commission (the Commission) under the Securities Act of 1933, as amended,
relating to the proposed issuance by the Company of common shares (the Shares), in connection
with the merger (the Merger) contemplated by the Agreement and Plan of Merger and Reorganization,
dated as of April 14, 2005, as amended May 9, 2005 (the Merger Agreement), among the Company,
Stantec Consulting California Inc. and The Keith Companies, Inc. (Keith). It is our
understanding that, upon consummation of the Merger, each outstanding share of common stock of
Keith (other than certain shares of common stock of Keith that will be cancelled) will be converted
into the right to receive cash and Shares, all as more fully described in the Registration
Statement. This opinion is being delivered in connection with the Registration Statement, to which
this opinion appears as an exhibit. We have examined the Registration Statement and the Merger Agreement. We also have examined the
originals, or duplicate, certified, conformed, telecopied or photostatic copies, of such corporate
records, agreements, documents and other instruments and have made such other investigations as we
have considered necessary or relevant for the purposes of this opinion. With respect to the
accuracy of factual matters material to this opinion, we have relied upon certificates or
comparable documents and representations of public officials and of officers and representatives of
the Company. In giving this opinion, we have assumed the genuineness of all signatures, the legal capacity of
natural persons, the authenticity of all documents submitted to us as originals, the conformity to
authentic original documents of all documents submitted to us as duplicates, certified, conformed,
telecopied or photostatic copies and the authenticity of the originals of such latter documents.




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Fraser Milner Casgrain llpStantec Inc.
    
    Page 2
 
 Based and relying upon the foregoing, and subject to the qualifications, assumptions and
limitations stated herein, we are of the opinion that when the Shares shall have been issued in
accordance with the terms of the Merger Agreement, the Shares will be validly issued, fully paid
and non-assessable. This opinion is based upon and limited to the laws of the Province of Alberta and the laws of
Canada applicable therein. We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Registration Statement
and to the use of our name where it appears in the proxy statement/prospectus included in the
Registration Statement. In giving this consent, we do not hereby admit that we are within the
category of persons whose consent is required under Section 7 of the Securities Act of 1933, as
amended, or the rules and regulations of the Securities and Exchange Commission thereunder. This opinion is addressed to you for your sole benefit in connection with the above-described
transaction. This opinion may not be relied upon by you for any other purpose or relied upon by, or
furnished to, any other person, firm or corporation, or quoted from or referred to in any document
other than the Registration Statement, or used for any other purpose, without our prior written
consent. This opinion is given as of the date hereof and we disclaim any obligation or undertaking
to advise the addressee hereof of any change in law or fact affecting or bearing upon this opinion
occurring after the date hereof which may come or be brought to our attention. Yours truly, /s/  Fraser Milner Casgrain LLP  EDMDOCSRROTH|929219-1