William Collier Jr. (February 12, 1902 – February 5, 1987), also known as Buster Collier, was an American film actor and producer. The son of actors, he began his career as a child actor in theater before making his film debut during the silent era. He achieved popularity in the 1920s and 1930s, demonstrating a successful transition to sound films. His most significant performances include roles in highly successful films such as *The Dawn Patrol* (1930), the gangster classic *Little Caesar* (1931), and the epic Western *Cimarron* (1931), which won the Academy Award for Best Picture. After a gradual decline in his acting career in the mid-1930s, he moved to Europe and became an established film producer, working primarily in the United Kingdom. For his contribution to the motion picture industry, he was awarded a star on the Hollywood Walk of Fame.