Ready Player One is a 2018 American science fiction action film based on Ernest Cline's novel of the same name. The film was co-produced and directed by Steven Spielberg, written by Cline and Zak Penn, and stars Tye Sheridan, Olivia Cooke, Ben Mendelsohn, Lena Waithe, T.J. Miller, Simon Pegg and Mark Rylance. The film is set in 2045, where much of humanity uses the OASIS, a virtual reality simulation, to escape the real world. A teenage orphan finds clues to a contest that promises ownership of the OASIS to the winner, and he and his allies try to complete it before an evil corporation can do so.

Development of the film first began in 2010 when Warner Bros. acquired the rights to the book. In July 2015, Spielberg signed on to direct and produce the film, with casting commencing in September 2015. Filming began in England in June 2016 and was completed in September that year. The visual effects were handled by Industrial Light & Magic, Digital Domain and Territory Studio, with some pre-visualization work done by The Third Floor, Inc.. As with the novel, many popular culture references appear throughout the film, including those to the Back to the Future franchise, The Iron Giant, The Shining and the Godzilla franchise.

Ready Player One premiered at South by Southwest in Austin, Texas on March 11, 2018, and was theatrically released in the United States on March 29, 2018, by Warner Bros. Pictures. The film received generally positive reviews from critics, who praised Spielberg's direction, the visual effects, brisk pacing, and the performances of both Sheridan and Rylance. It was also a commercial success, grossing around $607 million worldwide against a $155–175 million budget, and earned a nomination for Best Visual Effects at the 91st Academy Awards, 24th Critics' Choice Awards, and 72nd British Academy Film Awards. Ready Player One was awarded the title of Best Science Fiction Film at the 45th Saturn Awards, and a further two Outstanding Achievement Awards from the Visual Effects Society. A sequel is in development.