William "Shorty" Cantlon (1904 in Paris, Illinois – May 30, 1947 in Indianapolis, Indiana) was an American racecar driver. He was killed on May 30, 1947, while racing in the 1947 Indianapolis 500 on lap 40 after swerving into the outside retaining wall to avoid the spinning car of Bill Holland, who recovered from the spin to finish second. After his body was removed, Cantlon's car was left resting against the wall until the end of the 200-lap race.