The Eclipse Star Destroyer (or Eclipse-class Star Dreadnought in present-day military terms) is a class of Imperial warship from the Star Wars Expanded Universe. It was first mentioned in the Dark Empire series of comic books.

The Eclipse-class was constructed by Kuat Drive Yards, like many Imperial starships. The first of this class, the Eclipse, became the reborn Emperor's flagship. The ship had a jet black hull and was 17 kilometers long. It was one of the most heavily armed ships of all time. It carried over a thousand turbolaser and heavy turbolaser cannons. It also had powerful shields and heavy armor, making it difficult to destroy in space combat. The most important feature was a superlaser cannon located on the bow of the Eclipse. Although it was not as powerful as the superlaser on the Death Star, it was capable of cracking a planet's crust. For space combat, it held 600 TIE Interceptors and 96 TIE Bombers, divided into 58 squadrons. For ground assualt, it carried 150,000 Imperial Stormtroopers, 100 AT-ATs, and five prefabricated bases. The Eclipse was crewed by over 700,000 personnel.

The power of the Eclipse's superlaser as described is self-contradictory. It has been described as 2/3rds the power of the Death Star's prime weapon. Such a weapon would be more than sufficient to destroy a planet. There is some speculation as to whether the 2/3rds number refers to the magnitude of the energy release as opposed to the total value; this would put the main weapon below the threshold neccessary to destroy a planet.

The Eclipse was destroyed along with the reborn Emperor when Luke Skywalker and his sister Princess Leia managed to disrupt the Emperor's control of a titanic Force storm, a massive conflagration of Dark Side energy that the Emperor had summoned in order to wipe out the massed New Republic fleet. Afterwards, a second Eclipse-class ship was built, dubbed the Eclipse II. Above the planet Byss, R2-D2 override and took control of the Eclipse II's computer banks. R2 then sent the Eclipse II on a collison course with the superweapon Galaxy Gun. The explosion destroyed the Eclipse II and the Galaxy Gun. One last projectile was pulled by Byss' gravity and hit the planet, destroying it.

See also: List of vehicles in Star Wars