The Galactic Empire is one of the main factions in the fictional universe of Star Wars. It is a galaxy-spanning regime established by the series' lead villain, Palpatine, to replace the Galactic Republic in Star Wars Episode III: Revenge of the Sith. The Galactic Empire is introduced in Star Wars Episode IV: A New Hope. The Empire also appears in Star Wars Episode V: The Empire Strikes Back, and in Star Wars Episode VI: Return of the Jedi.
The Empire's origins are explained in Star Wars Episode III: Revenge of the Sith, where it replaces the Galactic Republic in the midst of a galactic civil war orchestrated by Palpatine, then the Republic's Supreme Chancellor. In a scene towards the end of the film, Palpatine appoints himself Emperor in the presence of the Galactic Senate, afterward the Imperial Senate. By the time of A New Hope, the Empire has transformed into a fully totalitarian regime, with opposition in the form of the Rebel Alliance.
The Galactic Empire is described in various Star Wars media as a brutal dictatorship, one based on "tyranny, hatred of nonhumans, brutal and lethal force, and, above all else, constant fear."