William B. Duke (December 5, 1857 - January 26, 1926) was a U. S. Racing Hall of Fame trainer of Thoroughbred racehorses who won eight French Classic Races, was a five-time national champion trainer in France and, after returning to the United States in late 1924, won the 1925 Kentucky Derby and the 1925 Preakness Stakes. Little more than a year after he returned to the United States, William Duke died at his home in Wellsville, New York on January 26, 1926.