Freddie Highmore as George Zinavoy

Emma Roberts as Sally Howe

Michael Angarano as Dustin

Elizabeth Reaser as Charlotte Howe

Alicia Silverstone as Ms. Herman

Sasha Spielberg as Zoe

Marcus Carl Franklin as Will

Ann Dowd as Mrs. Grimes

Blair Underwood as Principal

Rita Wilson as Vivian Sargent

Sam Robards as Jack Sargent

Sophie Lane Curtis as Chastity

Maya Ri Sanchez as Cynthia

Ann Harada as Mrs. Dougherty

Jarlath Conroy as Harris McElroy

Andrew Levitas as Javier

Dan Leonard as Nick

Lindsay-Elizabeth Hand as Sally's Friend (uncredited)