William Smith Fraser (July 19, 1852 – April 27, 1897) was an American architect based in Pittsburgh, Pennsylvania.

Fraser is best known for his designs for the Herron Hill Pumping Station (1896), a City of Pittsburgh Historic Structure, and the original Joseph Horne Company Department Store (1893), a Pittsburgh History and Landmarks Foundation Historic Landmark, though substantially rebuilt by later architects.

Fraser was born July 19, 1852,[1] in Wellsville, Ohio and studied architecture in New York City and in the office of William Burges in England.

In all, he completed about 50 commissions for homes, churches, schools, and commercial buildings, in a variety of styles, before his death from cancer in 1897.

William Harvey Birkmire, in his 1898 book The Planning and Construction of High Office-Buildings, summarized the lessons learned from the Horne fire:[4] "...the protection of buildings against fire does not stop with the rearing of a steel skeleton and clothing it with an integument of incombustible and non-conducting material; but includes impervious outer walls, with a minimum of window and door areas, and these protected by fire-proof shutters, frequent dividing-walls and enclosed elevator-shafts, stairways, and similar vertical openings.Fraser died on April 27, 1897, one week before the fire and did not see his fireproof design put to the test.