Sir Percy (foaled 2003) is a British Thoroughbred race horse and sire. In a career which lasted from July 2005 to June 2007 he ran ten times and won five races. he was among the leading British two-year-olds of 2005, when his win included the Dewhurst Stakes. In the following year he recorded his most important success when winning the Epsom Derby. He was retired to stud after three unsuccessful starts in 2007.