Northern Dancer was a Thoroughbred that, in 1964, became the first Canadian-bred horse to win the Kentucky Derby. After being retired from racing, he became one of the most successful sires of the 20th century. He is considered a Canadian icon and was inducted into the Canadian Sports Hall of Fame in 1965. Induction into the Racing Hall of Fame in both Canada and the United States followed in 1976. As a competitor, The Blood-Horse ranked him as one of the top 100 U.S. Thoroughbred racehorses of the 20th century. As a sire of sires, his influence on the breed is still felt worldwide.

The Thoroughbred is a horse breed developed for horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are considered "hot-blooded" horses that are known for their agility, speed, and spirit.