The Triple Crown of Thoroughbred Racing, often shortened to Triple Crown, is a series of horse races for Thoroughbreds, often restricted to three-year-olds. Winning all three of these Thoroughbred horse races is considered the greatest accomplishment in Thoroughbred racing. The term originated in mid-19th-century England and nations where Thoroughbred racing is popular each have their own Triple Crown series.

Horse racing is an equestrian performance sport, typically involving two or more horses ridden by jockeys over a set distance for competition. It is one of the most ancient of all sports, as its basic premise – to identify which of two or more horses is the fastest over a set course or distance – has been mostly unchanged since at least classical antiquity.