The Mercury Theatre was an independent repertory theatre company founded in New York City in 1937 by Orson Welles and producer John Houseman. The company produced theatrical presentations, radio programs and motion pictures. The Mercury also released promptbooks and phonographic recordings of four Shakespeare works for use in schools.After a series of acclaimed Broadway productions, the Mercury Theatre progressed into its most popular incarnation as The Mercury Theatre on the Air. The radio series included one of the most notable and infamous radio broadcasts of all time, "The War of the Worlds", broadcast October 30, 1938.

 The Mercury Theatre on the Air produced live radio dramas in 1938–1940 and again briefly in 1946.In addition to Welles, the Mercury players included Ray Collins, Joseph Cotten, George Coulouris, Martin Gabel, Norman Lloyd, Agnes Moorehead, Paul Stewart, and Everett Sloane. Much of the troupe would later appear in Welles's films at RKO, particularly Citizen Kane and The Magnificent Ambersons.