Homer Simpson / Itchy / Barney / Abe Simpson / Stage Manager / Krusty the Clown / Mayor Quimby / Mayor's Aide / Multi-Eyed Squirrel / Panicky Man / Sideshow Mel / Mr. Teeny / EPA Official / Kissing Cop / Bear / Boy on Phone / NSA Worker / Officer / Santa's Little Helper / Squeaky-Voiced Teen (voice)
Homer Simpson / Aristotle Amadopolis (voice)
Mr. Mysterio / Woodenleg Wally (voice)
Auctioneer / Horse Trader (voice)
Grandpa 'Steely' Phil / Nick Vermicelli (voice)
Tall Customs Dog / Angel Dog #1 (voice)
Homer Simpson (voice) (uncredited)
Wild Bill Hickok / Clerk / Cheyenne #2 (voice)
Gordon Johnson/Bryan Lynn
Additional Voices (voice)
Homer Simpson (voice) (uncredited)
Homer Simpson / Willie / Grampa Simpson/ Kodos/ Various (voice)
Iron Shoes / Priest (voice)
Homer Simpson / Grampa Simpson (voice)
Homer Simpson / Grampa Simpson (voice)
Diane's Teacher (uncredited)
Thing One / Thing Two (voice)
Animated Babysitter (voice)
Homer Simpson / Abraham 'Grampa' Simpson (voice)
Homer Simpson / Barney Gumble (voice)
Homer Simpson / Abe Simpson / Barney Gumble / Krusty (voice)
David Champion / Homer Simpson
Mr. Horner / Franklin the Frog (voice)
Commissioner Jerry Salerno
Wesker / Scarface (voice)
Boris / Captain Howdy / Coluans (voice)
Voodoo Man / Muck Luck (voice)
Homer Simpson / Abe Simpson / Barney Gumble / Krusty (voice)
Kaznian Astronaut / Socialite / Photographer (voice)
Private Cleoutus Dobbs / Baxter (voice)
Additional Voice Talent (voice)
Boney / Bureauocrates (voice)
Homer / Nectar guy (voice)
Grandpa Phil / Nick Vermicelli (voice)
Animal Control Officer (voice)
Grandpa Phil / Chicken Man (voice)
Grandpa Phil / Cop #1 (voice)
Grandpa Phil / Nolo (voice)
Grandpa Phil / Grandpa Phil's Father / Jolly Olly Man (voice)
Grandpa Phil / Judge (voice)
Grandpa Phil / Reporter (voice)
Earl / Janitor #2 (voice)
Jonathan / Phone Caller / Sailing Instructor (voice)
Slam-bot / Fussy-Boy (voice)
Robot Sentry 1 / Robot Sentry 2 (voice)
Senator Banda / Garron / Nifty Joe (voice)
Hunter #1 / Hunter #2 / Lackey / Casey Kasemish DJ (voice)
Resort Manager / Alien / Captain Alien (voice)
Officer McBride / Police Officer (voice)
Loudspeaker Announcer (voice)
Mr. Groote/Mr. Brooks (voice)