George Orson Welles (May 6, 1915 – October 10, 1985) was an American actor and filmmaker. Remembered for his innovative work in film, radio, and theatre, he is considered among the greatest and most influential filmmakers of all time.

Aged 21, Welles directed high-profile stage productions for the Federal Theatre Project in New York City—starting with a celebrated 1936 adaptation of Macbeth with an African-American cast, and ending with the political musical The Cradle Will Rock in 1937. He and John Houseman founded the Mercury Theatre, an independent repertory theatre company that presented productions on Broadway through 1941, including a modern, politically charged Caesar (1937). In 1938, his radio anthology series The Mercury Theatre on the Air gave Welles the platform to find international fame as the director and narrator of a radio adaptation of H. G. Wells's novel The War of the Worlds, which caused some listeners to believe a Martian invasion was occurring. The event rocketed the 23-year-old to notoriety.

His first film was Citizen Kane (1941), which he co-wrote, produced, directed and starred in as the title character, Charles Foster Kane. Cecelia Ager, reviewing it in PM Magazine, wrote: "Seeing it, it's as if you never really saw a movie before." It has been consistently ranked as one of the greatest films ever made. He directed twelve other features, the most acclaimed of which include The Magnificent Ambersons (1942), Othello (1951), Touch of Evil (1958), The Trial (1962), and Chimes at Midnight (1966). Welles also acted in other directors' films, playing Rochester in Jane Eyre (1943), Harry Lime in The Third Man (1949), and Cardinal Wolsey in A Man for All Seasons (1966).

His distinctive directorial style featured layered and nonlinear narrative forms, dramatic lighting, unusual camera angles, sound techniques borrowed from radio, deep focus shots and long takes. He has been praised as "the ultimate auteur". Welles was an outsider to the studio system and struggled for creative control on his projects. He received an Academy Award and three Grammy Awards among other honors and accolades such as the Golden Lion in 1947, the Palme D'Or in 1952, the Academy Honorary Award in 1970, the AFI Life Achievement Award in 1975, and the British Film Institute Fellowship in 1983. British Film Institute polls in 2002 voted him the greatest film director ever. In 2018, he was included in the list of the greatest Hollywood actors of all time by The Daily Telegraph. Micheál Mac Liammóir, who worked with the 16-year-old Welles in Dublin's Gate Theatre and played Iago in his film Othello (1951), wrote that "Orson's courage, like everything else about him, imagination, egotism, generosity, ruthlessness, forbearance, impatience, sensitivity, grossness and vision is magnificently out of proportion."