Old Rosebud (March 13, 1911 – May 23, 1922) was an American Thoroughbred racehorse whose pedigree traced to the influential sire Eclipse, and through Eclipse to the founding stallion, the Darley Arabian. In the list of the top 100 U.S. thoroughbred champions of the 20th Century by Blood-Horse magazine, Old Rosebud ranks 88th. Despite a successful racing career, Old Rosebud was plagued by ailments throughout his life, culminating in a fatal injury at a claiming race when he was 11 years old.