Zachary Gordon
Greg Heffley
Robert Capron
Rowley Jefferson
Steve Zahn
Frank J. Heffley
Devon Bostick
Rodrick Heffley
Rachael Harris
Susan Heffley
Chloë Grace Moretz
Angie Steadman
Laine MacNeil
Patty Farrell
Andrew McNee
Coach Malone
Connor Fielding
Manny Heffley
Owen Fielding
Manny Heffley
Karan Brar
Chirag Gupta
Grayson Russell
Fregley
Alex Ferris
Collin
Belita Moreno
Mrs. Norton
Rob LaBelle
Mr. Winsky
Nicholas Carey
Pete Hosey
Samuel Patrick Chu
Carter
Donnie MacNeil
Wade
Samantha Page
Shelley
Ava Hughes
Marley
Owen Best
Bryce Anderson
Cainan Wiebe
Quentin
Cole Heppell
Quentin's Sidekick
Harrison Houde
Darren Walsh
Severin Korfer
Dieter Muller
Jennifer Clement
Mrs. Flint
Karin Konoval
Mrs. Irvine
Raugi Yu
Vice Principal Roy
Kaye Capron
Rowley's Mom
Jake D. Smith
Archie Kelly
Talon Dunbar
Arthur
Naomi Dane
Cheese Girl
Willem Jacobson
Cheese Boy
Sean Bygrave
Coach Brewer
Maxine Miller
Elderly Woman
Taya Clyne
Granddaughter
Nathaniel Marten
Grown-Up Greg
Peter New
Grown-Up Quentin
Nikki Frazer
Lunch Girl #1
Greta Makena Gibson
Lunch Kid #2
Nathan Smith
Kindergarten Boy
Kinua McWatt
Kindergarten Girl
Dylan Bell
Kindergarten Greg
Madison Bell
Kindergarten Patty
Adom Osei
Marty Porter
Alf Humphreys
Mr. Jefferson
Brent Chapman
Mr. Parnell
Rylee Stiles
Preston
Ryan Grantham
Rodney James
Ethan Shankaruk
Snot Kid
Jesse Wheeler
Unpopular 80s Boy
Paul Hubbard
Brock Branigan
Brett Dier
80s Breakdancer
Brandon Barton
80s Jock Boy
Cindy Busby
80s Popular Girl
Alicia Takase Lui
Audition Kid
Jay Sidhu
Audition Kid
Tori Christianson
Audition Kid
Emerald Schreier
Audition Kid
Ben Mitchell
Audition Kid
Haris Cash
Audition Kid
Mariah Crudo
Audition Kid
Alistair Abell
Male Reporter (voice)
Tara McGuire
Female Reporter (voice)
Aidan Gebert
Löded Diper
Cameron Krpan
Löded Diper
Paolo Tolfo
Löded Diper
Amy Esterle
Waitress (uncredited)