Wild Dayrell (1852–1870) was a British Thoroughbred racehorse and sire. In a career that lasted from October 1854 to September 1855 he ran four times and won three races including The Derby. He was an unusual Derby winner, as neither his owner nor his trainer had any previous experience of Thoroughbred racing. Wild Dayrell was retired to stud at the end of his three-year-old season, and had some success as a stallion, siring several good winners.

The title of champion, or leading, sire of racehorses in Great Britain and Ireland is awarded to the stallion whose offspring have won the most prize money in Britain and Ireland during the flat racing season. The current (2022) champion is Dubawi, who earned his first title after finishing runner-up multiple times.