Irving S. Brecher (January 17, 1914 – November 17, 2008) was a screenwriter who wrote for the Marx Brothers; he was the only writer to get sole credit on a Marx Brothers film including At the Circus in 1939 and Go West in 1940. He was also one of the numerous uncredited writers on the screenplay of 1939's The Wizard of Oz. Some of his other screenplays were Shadow of the Thin Man (1941), Ziegfeld Follies (1946) and Bye Bye Birdie (1963).