Assert (17 April 1979 – 1995) was an Irish Thoroughbred racehorse and sire. As a two-year-old he was beaten by Golden Fleece on his debut but went on to win the Beresford Stakes. In the following year he was again beaten by Golden Fleece in a trial race but went on to win four Group One races: the Prix du Jockey Club, Irish Derby, Benson & Hedges Gold Cup and Joe McGrath Memorial Stakes. He was rated the best middle-distance horse in Europe in 1982 by Timeform. He was retired to stud at the end of his three-year-old season and became a successful sire of winners.