2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick. The screenplay was written by Kubrick and Arthur C. Clarke, and it was inspired by multiple short stories by Clarke, including "The Sentinel" (1951). Clarke also published a novelisation of the film, in part written concurrently with the screenplay, after the film's release. 2001: A Space Odyssey stars Keir Dullea, Gary Lockwood, William Sylvester, and Douglas Rain and follows a voyage by astronauts, scientists, and the sentient supercomputer HAL 9000 to Jupiter to investigate an alien monolith.

The film is noted for its scientifically accurate depiction of spaceflight, pioneering special effects, and ambiguous themes. Kubrick avoided conventional cinematic and narrative techniques; dialogue is used sparingly, and there are long sequences accompanied only by music. The soundtrack incorporates numerous works of classical music, including pieces by composers such as Richard Strauss, Johann Strauss II, Aram Khachaturian, and György Ligeti.

2001: A Space Odyssey received diverse critical responses, ranging from those who saw it as darkly apocalyptic to those who saw it as an optimistic reappraisal of the hopes of humanity. Critics noted its exploration of themes such as human evolution, technology, artificial intelligence, and the possibility of extraterrestrial life. It was nominated for four Academy Awards, winning Kubrick the award for his direction of the visual effects. The film is now widely regarded as one of the greatest and most influential films ever made. In 1991, it was selected by the United States Library of Congress for preservation in the National Film Registry. In 2022, 2001: A Space Odyssey placed in the top ten of Sight & Sound's decennial critics' poll, and topped their directors' poll. A sequel, 2010: The Year We Make Contact, was released in 1984, based on the novel 2010: Odyssey Two.