Captain Rex, designation number CT-7567,^[a] is a fictional character in the Star Wars science fiction universe created by George Lucas and a main character of the animated The Clone Wars 2008 film and the related television series of the same name. He is a clone trooper of the Grand Army of the Republic, cloned from bounty hunter Jango Fett, and serves the Galactic Republic under the command of Jedi Anakin Skywalker and Ahsoka Tano. Since his introduction in The Clone Wars, he has also appeared in the 2014 Star Wars Rebels television series and in comics, novels, and video games of the Star Wars Legends expanded universe. Like all clone troopers in The Clone Wars and Rebels, Rex is voiced by Dee Bradley Baker.

He is physically distinguished from other clone troopers by his close-shaved blond hair, and he is identified by blue markings on his armor and by stylized hawk eyes painted on his helmet. Rex was also distinguished by his use of twin blaster pistols in combat.^[3] He is described as a reliable and exemplary soldier, considered by Anakin to be his «first-in-command». Rex is characterized as believing it his duty to not only carry out orders but also to protect the men under his command, but his belief in the Republic wavers over the course of the series.

Initial development for The Clone Wars film chose Alpha-17, featured in Star Wars: Republic, to be the primary clone trooper character. However, Lucas felt this created too much alliteration with the existing principal cast, and a new character was created instead. Rex was developed as the central personality to which the troopers around him aspired and featured in story arcs exploring his character development. Rex became a favorite among fans, consistently placing in fan polls and Star Wars character ranking lists.