Monster High is an American animated web series based on the eponymous then-freshman American fashion doll line created by Mattel, the first adaptation since its launch, which originally aired on YouTube from May 5, 2010, to February 9, 2018.

The series follows a group of teenage children of famous monsters in media and film who attend high school. Along with its feature-length direct-to-video films, this series serves as a platform to launch new doll characters. The web series finished its first run in 2015 with Volume 6, and got rebooted with a long-form 11-minute, 12-episode series order titled the Adventures of the Ghoul Squad. As of July 12, 2018, 189 web series episodes were produced and released – including the reboot series.