Scottish Union (1935–1954) was a British Thoroughbred racehorse and broodmare best known for winning the classic St Leger Stakes in 1938. He was one of the highest-rated British two-year-old in 1937, when his wins included the Middle Park Stakes at Newmarket Racecourse. In the following year he ran prominently in all three legs of the Triple Crown, finishing second in the 2000 Guineas and the Epsom Derby before his win in the Leger.