Monster High is an American fashion doll franchise created by Mattel in July, 2010. The characters are inspired by monster movies, sci-fi horror, thriller fiction, and various creatures therefore distinguishing them from most fashion dolls. They were created by Garrett Sander, with illustrations by Kellee Riley.

The Monster High franchise also includes other consumer products such as stationery, bags, key chains, various toys and video games. There are also Monster High TV specials, a web series, a direct to DVD movie, and software. Lisi Harrison is the author of the Monster High books. The characters are depicted as being either related to or as offspring of famous monsters such as Dracula, Frankenstein's Monster, the Mummy, Medusa, the Creature from the Black Lagoon, the Phantom of the Opera, and zombies and more. The characters are usually referred to as ghouls, rather than girls.