Donald David Dixon Ronald O'Connor (August 28, 1925 – September 27, 2003) was an American dancer, singer and actor. He came to fame in a series of films in which he co-starred with Gloria Jean, Peggy Ryan, and Francis the Talking Mule.

O'Connor was born into a vaudeville family, where he learned to dance, sing, play comedy, even slapstick. The most distinctive characteristic of his dancing style was its athleticism, for which he had few rivals. Yet it was his boyish charm that audiences found most engaging, and which remained an appealing aspect of his personality throughout his career. In his early Universal films, O'Connor closely mimicked the smart alec, fast-talking personality of Mickey Rooney of rival MGM Studio. For Singin' in the Rain, however, MGM cultivated a much more sympathetic sidekick persona, and that remained O'Connor's signature image.

His best-known work was his "Make 'Em Laugh" dance routine in Singin' in the Rain (1952), for which role O'Connor was awarded a Golden Globe. He also won a Primetime Emmy Award from four nominations and received two stars on the Hollywood Walk of Fame.