Dan Castellaneta
as Homer Simpson, Homer Simpson as Poochie as The Fonz, Krusty the Clown, Barney Gumble, Grampa Simpson, Mayor Quimby, Teen Homer, Coffee Shop Man, Al Gore, Stockbroker Bum, Big City Hick, Galacticus, Radioactive Man, Itchy, Robot in Human Suit, Tony Hawk's Dad, Scary Voice, Insignificant Ant, Shrek, and Lard Lad
Julie Kavner
as Marge Simpson and Selma Bouvier
Nancy Cartwright
as Lisa Simpson
Yeardley Smith
as Bart Simpson, Ralph Wiggum, and Nelson Muntz
Hank Azaria
as Apu Nahasapeemapetilon, Chief Wiggum, Moe Szyslak, Comic Book Man, Professor Frink, Cletus, Dr. Nick, Superintendant Chalmers, Sausage Truck Driver, Blue-Collar Slob, Yuppie Scum, Hipster Muppet, Taco Bell Chihuahua, Antonin Scalia, Mario, McGarnigle, Teen Cletus, Scary Clown Bed, Dirty-Faced Vagrant at Party, and himself
Harry Shearer
as Mr. Burns, Ned Flanders, Principal Skinner, Waylon Smithers, Kent Brockman, Lenny, Dr. Hibbert, Judge Snyder, Dr. Marvin Monroe, Clarence Thomas, Baby Tom Brokaw, God, Scratchy, Sideshow Hal, Guardian of Forever, Krunk Lawyer, Nigel Tufnel, Ronald Reagan, Bonejacker, Pizza Demon, and Older Bort
Pamela Hayden
as Milhouse, Jimbo Jones, and Younger Bort
Maggie Roswell
as Maggie Simpson and BortMom
Russi Taylor
as Martin Prince
Tress MacNeille
as Generic Old Lady Voice, Generic Businesswoman Voice, and Generic Small Child Voice From Every Cartoon Ever
Marcia Wallace
as Mrs. Krabappel
Karl Weidergott
as Carl
Frank Welker
as Santa's Little Helper, Snowball II, Spiderpig, and V'ger
Kelsey Grammer
as Sideshow Bob
Doris Grau
as Lunchlady Doris
Phil Hartman
as Troy McClure and Lionel Hutz
Joe Mantegna
as Fat Tony and Marge's father
Billy West
as Fry
Erin Brokovitch
as herself
Albert Brooks
as Hank Scorpio
Danny DeVito
as Herb Powell and Bread Goblin
Minnie Driver
as Grievance Counseler
Will Ferrell
as Jack Black
Isla Fisher
as Patty Bouvier
Mel Gibson
as Old Jewish Man
Green Day
as Blink-182
Emilio Estevez
as Paradox Clone Homer
Arnold Schwarzenegger
as Rainier Wolfcastle
Meryl Streep
as Jessica Lovejoy
Tom Waits
as Dr. Marvin Monroe (singing)
and
President George W. Bush
as himself
