Sickle was a British-bred thoroughbred racehorse who was later exported to the US where he was twice the leading sire in North America. He was bred by Edward Stanley, 17th Earl of Derby.

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.