William Singer Moorhead (April 8, 1923 – August 3, 1987) was a Democratic member of the U.S. House of Representatives from Pennsylvania.
Moorhead was born in Pittsburgh, PA, the son of prominent attorney William Singer Moorhead, Sr (1883–1952). He attended Shady Side Academy, graduated from Phillips Andover Academy in 1941 and from Yale University in 1944, where he was a member of Skull and Bones. He served in the United States Navy from 1943 until he was discharged as a lieutenant (jg.) in 1946 with service in the Pacific Theater. He graduated from Harvard Law School in 1949. He served as Assistant City Solicitor of Pittsburgh from 1954 to 1957, as a member of Allegheny County Housing Authority from 1956 to 1958, and the Pittsburgh Art Commission in 1958.
He was elected in 1959 as a Democrat to the 86th Congress and to the ten succeeding Congresses. He was not a candidate for reelection in 1980.