Donald David Dixon Ronald O’Connor (August 28, 1925 – September 27, 2003) was an American dancer, singer, and actor who came to fame in a series of movies in which he co-starred alternately with Gloria Jean, Peggy Ryan, and Francis the Talking Mule. Perhaps his most famous performance was as Gene Kelly's friend and colleague in Singin’ in the Rain (1952).

Although he always considered Danville, Illinois his home town, Donald O’Connor was born in St. Elizabeth Hospital, Chicago, Illinois, into an Irish family of vaudeville entertainers. Tragedy struck his family when, as a toddler, he and his sister Arlene were involved in an automobile accident outside the theater the family was playing in Hartford, CT, which resulted in her death. His father died of a heart attack only a few weeks later in Brockton, MA.

O'Connor broke into films in 1937, usually playing impetuous kids. He scored a huge personal success opposite Bing Crosby in Sing, You Sinners, and even at age 12 displayed excellent comedic timing. Paramount Pictures kept him busy in both A and B pictures, including Tom Sawyer, Detective and Beau Geste, until 1940, when the now-adolescent O'Connor had outgrown kid roles. He returned to vaudeville for more than a year.