Zachary Gordon
as Greg Heffley

Robert Capron
as Rowley Jefferson

Steve Zahn
as Frank J. Heffley

Devon Bostick
as Rodrick Heffley

Rachael Harris
as Susan Heffley

Chloë Grace Moretz
as Angie Steadman

Laine MacNeil
as Patty Farrell

Andrew McNee
as Coach Malone

Connor Fielding
as Manny Heffley

Owen Fielding
as Manny Heffley

Karan Brar
as Chirag Gupta

Grayson Russell
as Fregley

Alex Ferris
as Collin

Belita Moreno
as Mrs. Norton

Rob LaBelle
as Mr. Winsky

Nicholas Carey
as Pete Hosey

Samuel Patrick Chu
as Carter

Donnie MacNeil
as Wade

Samantha Page
as Shelley

Ava Hughes
as Marley

Owen Best
as Bryce Anderson

Cainan Wiebe
as Quentin

Cole Heppell
as Quentin's Sidekick

Harrison Houde
as Darren Walsh

Severin Korfer
as Dieter Muller

Jennifer Clement
as Mrs. Flint

Karin Konoval
as Mrs. Irvine

Raugi Yu
as Vice Principal Roy

Kaye Capron
as Rowley's Mom

Jake D. Smith
as Archie Kelly

Talon Dunbar
as Arthur

Naomi Dane
as Cheese Girl

Willem Jacobson
as Cheese Boy

Sean Bygrave
as Coach Brewer

Maxine Miller
as Elderly Woman

Taya Clyne
as Granddaughter

Nathaniel Marten
as Grown-Up Greg

Peter New
as Grown-Up Quentin

Nikki Frazer
as Lunch Girl #1

Greta Makena Gibson
as Lunch Kid #2

Nathan Smith
as Kindergarten Boy

Kinua McWatt
as Kindergarten Girl

Dylan Bell
as Kindergarten Greg

Madison Bell
as Kindergarten Patty

Adom Osei
as Marty Porter

Alf Humphreys
as Mr. Jefferson

Brent Chapman
as Mr. Parnell

Rylee Stiles
as Preston

Ryan Grantham
as Rodney James

Ethan Shankaruk
as Snot Kid

Jesse Wheeler
as Unpopular 80s Boy

Paul Hubbard
as Brock Branigan

Brett Dier
as 80s Breakdancer

Brandon Barton
as 80s Jock Boy

Cindy Busby
as 80s Popular Girl

Alicia Takase Lui
as Audition Kid

Jay Sidhu
as Audition Kid

Tori Christianson
as Audition Kid

Emerald Schreier
as Audition Kid

Ben Mitchell
as Audition Kid

Haris Cash
as Audition Kid

Mariah Crudo
as Audition Kid

Alistair Abell
as Male Reporter (voice)

Tara McGuire
as Female Reporter (voice)

Aidan Gebert
as Löded Diper

Cameron Krpan
as Löded Diper

Paolo Tolfo
as Löded Diper

Amy Esterle
as Waitress (uncredited)