John Florence Sullivan (May 31, 1894 – March 17, 1956), known professionally as Fred Allen, was an American comedian. His absurdist topically-pointed radio program The Fred Allen Show (1932–1949) made him one of the most popular and forward-looking humorists in the Golden Age of American radio.

Allen's first taste of radio came while he and Portland Hoffa waited for a promised slot in a new Arthur Hammerstein musical. In the interim, they appeared on a Chicago station's program, WLS Showboat, into which Allen recalled, "Portland and I were presented... to inject a little class into it." Their success in these appearances helped their theater reception. Live audiences in the Midwest liked to see their radio favorites in person even if Allen and Hoffa would be replaced by Bob Hope when the radio show moved to New York several months afterward.

The couple eventually got their Hammerstein show, Polly, which opened in Delaware and made the usual tour before hitting Broadway. Also in that cast was a young Englishman named Archie Leach, who received as many good notices for his romantic appeal as Allen got for his comic work. Hammerstein retooled the show before he brought it to New York by replacing everyone but two women and Allen. Leach decided to buy an old car and drive to Hollywood. "What Archie Leach didn't tell me," Allen remembered, "was that he was going to change his name to Cary Grant."

Polly never succeeded in spite of several retoolings, but Allen went on to successful shows like The Little Show (1929–30) and Three's a Crowd (1930–31), which eventually led to his full-time entry to radio in 1932.