Posse (15 May 1977–after 1991) was an American-bred, British-trained
Thoroughbred racehorse and sire. He ran only six times, winning twice, in a racing career which lasted from October 1979 until July 1980. As a three-year-old he was promoted to second after a controversial race for the
2000 Guineas but showed his best form in summer when he established himself as one of the leading milers in Europe with wins in the
St. James's Palace Stakes and
Sussex Stakes. He was retired to stud at the end of the year and had some success as a sire of winners.