William Patrick "Parry" O'Brien was an American shot put champion. He competed in four consecutive Summer Olympics where he won two gold medals and one silver medal (1960). In his last Olympic competition (1964) he placed fourth. For all of these accomplishments, O'Brien was inducted into the IAAF and U.S. Olympic halls of fame.

The shot put is a track and field event involving "putting" (throwing) a heavy spherical ball—the shot—as far as possible. For men, the sport has been a part of the modern Olympics since their revival (1896), and women's competition began in 1948.