A Death Star (officially the DS-1 Orbital Battle Station) is a fictional moon-sized spacestation and superweapon appearing in the Star Wars movies and expanded universe. It is capable of destroying a planet with a single destructive energy beam.

Although particular details, such as the superlaser's location, shifted between different concept models during production of Star Wars Episode IV: A New Hope, the notion of the Death Star being a large, spherical space station was consistent in all of them.The Death Star was created by the dean of special effects John Stears.The buzzing sound counting down to the Death Star firing its superlaser comes from the Flash Gordon serials.Portraying an incomplete yet powerful space station posed a problem for Industrial Light & Magic's modelmakers for Star Wars Episode VI: Return of the Jedi.Only the front side of the 137-centimeter model was completed, and the image was flipped horizontally for the final film.Both Death Stars were depicted by a combination of complete and sectional models and matte paintings. The original Death Star first appears in its completed form in Star Wars Episode IV: A New Hope. Commanded by Grand Moff Tarkin (Peter Cushing), it is the Galactic Empire's "ultimate weapon", a space station capable of destroying a planet with one shot of its superlaser. The film opens with Leia Organa (Carrie Fisher) transporting the station's schematics to the Rebel Alliance to aid them in destroying the Death Star. Tarkin orders the Death Star to destroy Leia's home world of Alderaan in an attempt to pressure her into giving him the location of the secret Rebel base; she gives them a (false) location, but Tarkin has Alderaan destroyed anyway. Later, Luke Skywalker (Mark Hamill) boards the station with his friends and rescues her; in the film's climactic battle scene, he uses his power in the Force to help him destroy the station.

In Return of the Jedi, set four years later, the Empire is building a new Death Star; it is half-finished throughout the film. Emperor Palpatine (Ian McDiarmid) and Darth Vader (David Prowse/James Earl Jones) send the Rebels false information that the station's weapons systems are not operational in order to lure them into a trap, and bring Skywalker on board to turn him to the dark side of the Force. In the film's climax, Vader throws Palpatine down the station's reactor core, killing him, and is mortally wounded in the process. Skywalker escapes with Vader's body moments before the Rebels destroy the station.

The first Death Star also appears in the Star Wars prequel trilogy: its schematics are visible in Star Wars Episode II: Attack of the Clones, and the end of Star Wars Episode III: Revenge of the Sith shows the Death Star early in its construction.

The Death Star explosions featured in the special edition of A New Hope and in Return of the Jedi are rendered with a Praxis effect, wherein a flat ring of matter erupts from the explosion.