Reese Witherspoon
Susan Murphy / Ginormica (voice)
Hugh Laurie
Dr. Cockroach Ph.D. (voice)
Rainn Wilson
Gallaxhar (voice)
Will Arnett
The Missing Link (voice)
Kiefer Sutherland
General W.R. Monger (voice)
Paul Rudd
Derek Dietl (voice)
Stephen Colbert
President Hathaway (voice)
Julie White
Wendy Murphy (voice)
Jeffrey Tambor
Carl Murphy (voice)
Amy Poehler
Computer (voice)
Ed Helms
News Reporter (voice)
Renée Zellweger
Katie (voice)
Sean Bishop
Private Bullhorn / Helicopter Pilot / Advisor Ortega (voice)
Rich Dietl
Commander / Advisor Smith (voice)
Rob Letterman
Secret Service Man #1 / Lieutenant (voice)
Tom McGrath
Wilson (voice)
Chris Miller
Advisor Cole / Army Commander Jones (voice)
Mike Mitchell
Advisor Wedgie (voice)
Kent Osborne
Technician Jerry (voice)
Latifa Ouaou
Advisor Ouaou / Mrs. Ronson / Female Advisor #2 / Panicked Guest (voice)
Geoffrey Pomeroy
Soldier #4 / Pilot / Soldier #3 / News Technician (voice)
David P. Smith
Soldier #1 / Advisor Jackson (voice)
Lisa Stewart
Bridesmaid Candy (voice)
Conrad Vernon
Advisor Hawk / Advisor Dither / Minister / Secret Service Man #2 / Mama Dietl (voice)
John Krasinski
Cuthbert (voice)
Stephen Kearin
Technician Bee (voice)