RKO Radio Pictures Inc., commonly known as RKO Pictures or simply RKO, was an American film production and distribution company, one of the "Big Five" film studios of Hollywood's Golden Age. The business was formed after the Keith-Albee-Orpheum theater chain and Joseph P. Kennedy's Film Booking Offices of America studio were brought together under the control of the Radio Corporation of America (RCA) in October 1928. RCA executive David Sarnoff engineered the merger to create a market for the company's sound-on-film technology, RCA Photophone, and in early 1929 production began under the RKO name. Two years later, another Kennedy concern, the Pathé studio, was folded into the operation. By the mid-1940s, RKO was controlled by investor Floyd Odlum.

Major film studios are production and distribution companies that release a substantial number of films annually and consistently command the significant share of box office revenue in a given market. In the American and international markets, the major film studios, often known simply as the majors or the Big Five studios, are commonly regarded as the five diversified media conglomerates whose various film production and distribution subsidiaries collectively command approximately 80 to 85% of U.S. box office revenue. The term may also be applied more specifically to the primary motion picture business subsidiary of each respective conglomerate.