Hiram Eugene Leigh (1860 – December 10, 1937) was an American Thoroughbred racehorse trainer/owner and breeder who had a highly successful career in the United States as well as in Europe. Born in Taylorville, Illinois, he was known by his middle name, Eugene, or as "Gene." In the 1870s, thirteen-year-old Leigh became involved in Quarter Horse racing on bush tracks in his native Illinois. After learning to condition Thoroughbreds for flat racing he set himself up as a trainer in a partnership with jockey Tom Kiley. Leigh was successful enough that in 1884 he was hired as the trainer of a major racing stable in St. Louis, Missouri owned by Col. Robert C. Pate.