Best friends George and Harold β along with their classmates and tyrannical principal β are recruited for a mysterious mission in outer space.
Captain Underpants / Mr. Krupp (voice), Captain Pandernuts / Purpk (voice)
Harold (voice), Dohlar (voice)
George (voice), Greego (voice)
Comic Narrator (voice), Garg (voice)
Mr. Gigglenose (voice), Narrator (voice), Abraham Lincoln (voice)
Moxie Swaggerman / Xemio (voice), Moxie Swaggerman / Hailey Comett (voice)
Mr. Meaner / Sqworg (voice), Sqworg (voice), Mr. Meaner / Mr. Nearme (voice)
Dr. Shifty Fitzgibbons / Jett Wingman (voice), Dr. Shifty Fitzgibbons / Jett Wingman / Itsius (voice)
Dupe Licitous (voice)
Livmen / Stewart / Statrew (voice)
Arice (voice)
Elbrib (voice)