The Academy Award for Best Original Screenplay is the Academy Award for the best script not based upon previously published material. Before 1940, there was an Academy Award for Best Story for writing. For 1940, it and the award in this article were separated into two awards. Beginning with the Oscars for 1957, the two categories were combined to honor only the screenplay.

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1940s

• 1940 The Great McGinty - Preston Sturges
• Angels Over Broadway - Ben Hecht
• Dr. Ehrlich's Magic Bullet - Norman Burnside, Heinz Herald, John Huston
• Foreign Correspondent - Charles Bennett, Joan Harrison
• The Great Dictator - Charlie Chaplin
• 1941 Citizen Kane - Herman Mankiewicz, Orson Welles
• The Devil and Miss Jones - Norman Krasna
• Sergeant York - Harry Chandlee, Abem Finkel, John Huston, Howard Koch
• Tall, Dark and Handsome - Karl Tunberg, Darrell Ware
• Tom, Dick and Harry - Paul Jarrico
• 1942 Woman of the Year - Michael Kanin, Ring Lardner Jr
• One of Our Aircraft is Missing - Michael Powell, Emeric Pressburger
• Road to Morocco - Frank Butler, Don Hartman
• Wake Island - W. R. Burnett, Frank Butler
• The War Against Mrs. Hadley - George Oppenheimer
• 1943 Princess O'Rourke - Norman Krasna
• Air Force - Dudley Nichols
• In Which We Serve - Noel Coward
• The North Star - Lillian Hellman
• So Proudly We Hail! - Allan Scott
• 1944 Wilson - Lamar Trotti
• Hail the Conquering Hero - Preston Sturges
• The Miracle of Morgan's Creek - Preston Sturges
• Two Girls and a Sailor - Richard Connell, Glays Lehman
• Wing and a Prayer - Jerome Cady
• 1945 Marie-Louise - Richard Schweizer
• Dillinger - Philip Yordan
• Music for Millions - Myles Connolly
• Salty O'Rourke - Milton Holmes
• What Next, Corporal Hargrove? - Harry Kurnitz
• 1946 The Seventh Veil - Muriel Box, Sydney Box
• The Blue Dahlia - Raymond Chandler
• Children of Paradise - Jacques Prévert
• Notorious - Ben Hecht
• Road to Utopia - Norman Panama, Melvin Frank
• 1947 The Bachelor and the Bobby-Soxer - Sidney Sheldon
• Body and Soul - Abraham Polonsky
• A Double Life - Ruth Gordon, Garson Kanin
• Monsieur Verdoux - Charlie Chaplin
• Shoeshine - Sergio Amidei, Adolfo Franci, C. G. Viola, Cesare Zavattini
• 1948 none given (Instead of the categories "Original Screenplay and "Screenplay", it was combined into one category, called "Screenplay")
• 1949 Battleground - Robert Pirosh
• Jolson Sings Again - Sidney Buchman
• Paisà - Alfred Hayes, Federico Fellini, Sergio Amidei, Marcello Pagliero, Roberto Rossellini
• Passport to Pimlico - T. E. B. Clarke
• The Quiet One - Helen Levitt, Janice Loeb, Sidney Meyers

(In 1949, the category was renamed "Story and Screenplay")