Quack (February 26, 1969 – January 17, 1995) was an American Thoroughbred racehorse who holds the world record for a three-year-old with the fastest mile and a quarter ever run on dirt.
Quack was a very large horse whose style was to lag behind early and finish with a devastating closing kick.
Though Quack had success early in his career with Hall of Fame jockey Bill Shoemaker, he found even more success with Hall of Fame jockey Don Pierce, whose first ride on him was the 1972 Hollywood Gold Cup.
Quack was a bay with a spot of white on his forehead bred and raced by Millard Waldheim's Bwamazon Farm.
Not eligible for the 1972 Kentucky Derby, Quack scored the most important win of his career that year in the Hollywood Gold Cup in which he defeated older horses while equaling the United States and world records for a mile and a quarter on dirt.