Doyoun (8 March 1985 – 5 December 2002) was a British Thoroughbred racehorse and sire, best known for winning the classic 2000 Guineas in 1978. In a racing career which lasted from October 1987 until October 1988 he ran seven times and won three races. After winning his only race as a two-year-old in 1987, Doyoun produced his most impressive performance on his three-year-old debut when he defeated Warning in the Craven Stakes.