Raiders of the Lost Ark is a 1981 American action-adventure film directed by Steven Spielberg from a screenplay by Lawrence Kasdan, based on a story by George Lucas and Philip Kaufman. Set in 1936, the film stars Harrison Ford as Indiana Jones, a globetrotting archaeologist vying with Nazi German forces to recover the long-lost Ark of the Covenant which is said to make an army invincible. Teaming up with his tough former romantic interest Marion Ravenwood (Karen Allen), Jones races to stop rival archaeologist René Belloq (Paul Freeman) from guiding the Nazis to the Ark and its power.

Lucas conceived Raiders of the Lost Ark in the early 1970s. Seeking to modernize the serial films of the early 20th century, he developed the idea further with Kaufman, who suggested the Ark as the film's goal. Lucas eventually focused on developing his 1977 film Star Wars. Development on Raiders of the Lost Ark resumed that year when he shared the idea with Spielberg, who joined the project several months later. While the pair had ideas for set pieces and stunts for the film, they hired Kasdan to fill in the narrative gaps between them. Principal photography began in June 1980 on a $20 million budget, and concluded that September. Filming took place on sets at Elstree Studios, England, and on location mainly in La Rochelle, France, Tunisia, and Hawaii.

Pre-release polling showed little audience interest in the film leading up to its June 12, 1981 release date, especially compared to Superman II. However, Raiders of the Lost Ark became the highest-grossing film of the year, earning approximately $354 million worldwide, and played in some theaters for over a year. It was also a critical success, receiving praise for its set pieces, humor, and action sequences. The film was nominated for several awards, and won five Academy Awards, seven Saturn Awards, and one BAFTA, among other accolades.

Raiders of the Lost Ark is considered by critics to be one of the greatest films ever made and has had a lasting influence on popular culture, spawning a host of imitators across several media and inspiring other filmmakers. The United States Library of Congress selected it for preservation in the National Film Registry in 1999. Raiders of the Lost Ark is the first entry in what became the Indiana Jones franchise, which includes four more films—Temple of Doom (1984), Last Crusade (1989), Kingdom of the Crystal Skull (2008), and Dial of Destiny (2023)—a television series, video games, comic books, novels, theme park attractions, and toys.