Seabiscuit (May 23, 1933 – May 17, 1947) was a champion thoroughbred racehorse in the United States who became the top money-winning racehorse up to the 1940s. He beat the 1937 Triple-Crown winner, War Admiral, by 4 lengths in a two-horse special at Pimlico and was voted American Horse of the Year for 1938.

A small horse, at 15.2 hands high, Seabiscuit had an inauspicious start to his racing career, winning only a quarter of his first 40 races, but became an unlikely champion and a symbol of hope to many Americans during the Great Depression.

Seabiscuit has been the subject of numerous books and films, including Seabiscuit: the Lost Documentary (1939); the Shirley Temple film The Story of Seabiscuit (1949); a book, Seabiscuit: An American Legend (1999) by Laura Hillenbrand; and a film adaptation of Hillenbrand's book, Seabiscuit (2003), that was nominated for the Academy Award for Best Picture.