George (voice)
Captain Underpants / Mr. Krupp (voice)
Professor Poopypants (voice)
Harold (voice)
Melvin (voice)
Edith (voice)
Ms. Ribble (voice) (as Dee Dee Rescher)
Mr. Rected (voice)
Tommy (voice)
Mr. Fyde (voice)
Ms. Dayken (voice)
George's Mom (voice)
Sad Girl (voice) (as Tiffany Bennicke)
Mime (voice)
Officer McPiggly (voice)
Goody Two-Shoes Girl (voice)
Nobel Moderator (voice)
Nobel Audience Member (voice)
Balloon Girl (voice)
Biggest Fan (uncredited)