William H. Turner, Jr. American horse trainer
William H. Turner Jr. (February 29, 1940 – December 31, 2021) was an American Thoroughbred flat racing trainer best known for winning the United States Triple Crown of Thoroughbred Racing in 1977 with Seattle Slew.

Turner maintained a public training stable and bloodstock consulting services, operating mainly in New York, Florida, and the Mid-Atlantic region. At the time of his retirement he had been training horses competing on the New York Racing Association circuit.