Nat Faxon

Captain Underpants / Mr. Krupp (voice)

Jay Gragnani

Harold (voice)

Ramone Hamilton

George (voice)

Sean Astin

Narrator / Mr Gigglenose (voice)

Dayci Brookshire

Jessica / Dressy (voice)

Clancy Brown

Mr. Ree (voice)

Jorge Diaz

Melvin / Stanley Peet / Melvin's Dad (voice)

Peter Hastings

Comic Narrator (voice)

Evan Kishiyama

Steve "Gooch" Yamaguchi (voice)

David Koechner

Mr. Meaner (voice)