William Thomas Cahill (June 25, 1912–July 1, 1996) was an American politician who was a Republican member of the U.S. House of Representatives from New Jersey from 1959 to 1970 and the Governor of New Jersey from 1970 to 1974.
Though born in Philadelphia, Pennsylvania, Cahill moved to New Jersey with his parents in 1919. He attended Camden Catholic High School in Camden, New Jersey, and graduated in 1929. Afterwards, Cahill graduated St. Joseph's College (now Saint Joseph's University) at Philadelphia in 1933. He returned to Camden to study at Rutgers School of Law , receiving his law degree in 1937.
In 1937 and 1938 Cahill was a special agent of the Federal Bureau of Investigation. In 1939 he was admitted to the bar and began his political career.
He died in Haddonfield, New Jersey and is interred at Calvary Cemetery in Cherry Hill Township, New Jersey.