Castle of Illusion Starring Mickey Mouse, known in Japan as I Love Mickey Mouse: Great Mysterious Castle Adventure (アイラブミッキーマウス ふしぎのお城大冒険 Ai Rabu Mikkī Mausu: Fushigi no o-shiro daibōken?), is a platform game developed by Sega and released for the Sega Mega Drive (Genesis) in November 1990. The game also was on a cartridge entitled "Disney Collection" bundled with QuackShot in 1996. An 8-bit version of the game, known as I Love Mickey Mouse's Castle Illusion (アイラブミッキーマウスのキャッスル・イリユージヨン Ai Rabu Mikkī Mausu no Kyassuru Irūjon?) in Japan, was later released for the Master System and Game Gear.
The game follows Mickey Mouse on a quest to save Minnie Mouse from the evil witch Mizrabel. It was the first game in Sega's long-running Illusion series of video games starring Mickey and was also a part of the second wave of games initially released for the Sega Mega Drive/Genesis which helped seal the console's reputation within the period until the release of Sonic the Hedgehog.
Castle of Illusion was very well received by critics, especially the original 16-bit version. It was re-released in 1998 in Japan as part of the Sega Ages: Mickey Mouse & Donald Duck for the Sega Saturn, which features both Castle of Illusion and QuackShot. A remake of the game by Sega Studios Australia was released for PlayStation Network, Xbox Live Arcade and PC in September 2013.