The American quarter horse is the fastest breed of horse in the world, followed closely by the thoroughbred. However, Arabian horses outpace other breeds in endurance racing.
The three major racing breeds in the United States are the quarter horse, the thoroughbred and the Arabian. When comparing sprinting speed, the quarter horse is the fastest. The breed got its name from its speed over ¼-mile tracks. Thoroughbred races tend to be longer, although they have sprints as well. Arabians are the slowest over short distances, but they are known for their endurance. They excel at racing distances of 50 miles or more, which are ridden at a much slower overall pace.