William Prentice Cooper, Jr. (September 28, 1895 – May 18, 1969) was an American politician who served as Governor of Tennessee from 1939 to 1945. He led the state's mobilization efforts for World War II, when over 300,000 Tennesseans joined the armed forces, and numerous defense-related facilities were established across the state. He later served as U.S. Ambassador to Peru (1946–1948), and chaired Tennessee's 1953 constitutional convention.