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.
His best-remembered gag was his long-running mock feud with friend and fellow comedian Jack Benny, but that was only part of his appeal. Radio historian John Dunning wrote that Allen was perhaps radio's most admired comedian and most frequently censored. A master ad libber, Allen often tangled with his network's executives and often barbed them on the air over the battles while developing routines whose style and substance influenced fellow comic talents, including Groucho Marx, Stan Freberg, Henry Morgan, and Johnny Carson; his avowed fans also included President Franklin D. Roosevelt, humorist James Thurber, and novelists William Faulkner, John Steinbeck, and Herman Wouk, who began his career writing for Allen.
Allen was honored with stars on the Hollywood Walk of Fame for contributions to television and radio.