Mid-day Sun (1934–1954) was a British Thoroughbred racehorse and sire. After showing little promise as a two-year-old in 1936, Mid-day Sun improved into top class performer at three. In 1937 he won five races including the Epsom Derby and the Hardwicke Stakes at Royal Ascot. He was retired to stud in 1938 but had little success as a stallion. He was the first winner of the Derby at Epsom to be owned by a woman.