* Brandon T. Jackson as Grover Underwood
* Alexandra Daddario as Annabeth Chase
* Sean Bean as Zeus
* Melina Kanakaredes as Athena
* Pierce Brosnan as Chiron
* Uma Thurman as Medusa
* Rosario Dawson as Persephone
* Steve Coogan as Hades
* Catherine Keener as Sally Jackson
* Joe Pantoliano as Gabe Ugliano
* Jake Abel as Luke Castellan