The Empire Strikes Back (also known as Star Wars: Episode V – The Empire Strikes Back) is a 1980 American epic space opera film directed by Irvin Kershner from a screenplay by Leigh Brackett and Lawrence Kasdan, based on a story by George Lucas. The sequel to Star Wars (1977), it is the second film in the Star Wars film series and the fifth chronological chapter of the "Skywalker Saga". Set three years after the events of Star Wars, the film recounts the battle between the malevolent Galactic Empire, led by the Emperor, and the Rebel Alliance, led by Luke Skywalker and Princess Leia. As the Empire goes on the offensive, Luke trains to master the Force so he can confront the Emperor's powerful disciple, Darth Vader. The ensemble cast includes Mark Hamill, Harrison Ford, Carrie Fisher, Billy Dee Williams, Anthony Daniels, David Prowse, Kenny Baker, Peter Mayhew, and Frank Oz.

Following the success of Star Wars, Lucas hired Brackett to write the sequel. After she died in 1978, he outlined the whole Star Wars saga and wrote the next draft himself, before hiring Raiders of the Lost Ark (1981) writer Kasdan to enhance his work. To avoid the stress he faced directing Star Wars, Lucas handed the responsibility to Kershner and focused on expanding his special effects company Industrial Light & Magic instead. Filmed from March to September 1979 in Finse, Norway, and at Elstree Studios in England, The Empire Strikes Back faced production difficulties, including actor injuries, illnesses, fires, and problems securing additional financing as costs rose. Initially budgeted at $8 million, costs had risen to $30.5 million by the project's conclusion.

Released on May 21, 1980, the highly anticipated sequel became the highest-grossing film that year, earning approximately $401.5 million worldwide. Unlike its lighthearted predecessor, Empire met with mixed reviews from critics, and fans were conflicted about its darker and more mature themes. The film was nominated for various awards and won two Academy Awards, two Grammy Awards, and a BAFTA, among others. Subsequent releases have raised the film's worldwide gross to $538–549 million and, adjusted for inflation, it is the 13th-highest-grossing film in the United States and Canada.

Since its release, The Empire Strikes Back has been critically reassessed and is now often regarded as the best film in the Star Wars series and among the greatest films ever made. It has had a significant impact on filmmaking and popular culture and is often considered an example of a sequel superior to its predecessor. The climax, in which Vader reveals he is Luke's father, is often ranked as one of the greatest plot twists in cinema. The film spawned a variety of merchandise and adaptations, including video games and a radio play. The United States Library of Congress selected it for preservation in the National Film Registry in 2010. Return of the Jedi (1983) followed Empire, concluding the original Star Wars trilogy. Prequel and sequel trilogies have since been released.