Superstar Leo is an Irish-bred, British-trained retired champion Thoroughbred racehorse and successful broodmare. She was named European Champion Two-Year-Old Filly at the Cartier Racing Awards and was the highest-rated two-year-old filly in the International Classification for 2000. In her championship season she won five races and finished second in the other three. She failed to win in five starts as a three-year-old and was then retired to stud.