Doyoun (8 March 1985 – 5 December 2002) was a British Thoroughbred racehorse and sire, best known for winning the classic 2000 Guineas in 1988. 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. He won the 2000 Guineas on his next appearance but failed to win again, although he did finish third in the Epsom Derby. He was retired to stud at the end of the season, and after a slow start to his breeding career, sired several important winners including Daylami and Kalanisi. He died in Turkey in 2002.