Milo Coy as Stan

Jack Black as Grown Up Stan (voice)

Lee Eddy as Mom

Bill Wise as Dad

Natalie L'Amoreaux as Vicky

Josh Wiggins as Steve

Jessica Brynn Cohen as Jana

Sam Chipman as Greg

Danielle Guilbot as Stephanie

Zachary Levi as Kranz

Glen Powell as Bostick

Larry Jack Dotson as Grandfather

Mona Lee Fultz as Grandmother #1

Jennifer Griffin as Grandmother #2

Holt Boggs as Sam The Rocket Man

Reese Armstrong as Tony

Natalie Joy as Music Class Teacher

Suzanne Deal Booth as Science Teacher

Chris Olson as Principal Cowan

Samuel Davis as Pinball Buyer

Mia Gonzalez as Statue-Maker Kid

Brian Villalobos as Bales

Chris Zurcher as Jack

Alex Fink as Kid on Astroway

Zia Kinzy as Young Lady on Astroway

David DeLao as Mr. St. George

Noah Randall as Drive-In Employee

Athena Wintle as Mindy

Xavier Patterson as Emanuel

Nick Stevenson as SIMSUP

William Carroll as Abominable Snowman

Avery Joy Davis as Lisa (uncredited)

Christian Moran as Hoodlum (uncredited)

Nicholas Andrew Rice as NASA Controlman (uncredited)

Keslee Blalock as AstroWorld Kid (uncredited)

Brent A. Riggs as Service Station Attendant (uncredited)

P. Michael Hayes II as SIMSUP (uncredited)

Flint Nattinger as Laughing Boy (uncredited)