Riddlesworth (1828–1843) was a British Thoroughbred racehorse. He raced in April and May 1831, in a career that lasted less than seven weeks. He won four of his five starts, including the Riddlesworth Stakes, 2000 Guineas Stakes and Newmarket Stakes. On his final start he finished second in the Derby. Riddlesworth was owned by George Child Villiers, 5th Earl of Jersey, and trained by James Edwards. As a stallion he stood in Germany and the United States, but didn't leave many notable foals.