Jacob Tremblay

Auggie

Julia Roberts

Isabel

Owen Wilson

Nate

Izabela Vidovic

Via

Noah Jupe

Jack Will

Millie Davis

Summer

Bryce Gheisar

Julian

Mandy Patinkin

Mr. Tushman

Danielle Rose Russell

Miranda

Daveed Diggs

Mr. Browne

Mark Dozlaw

Teenage Doctor

Rukiya Bernard

Nurse

Elle McKinnon

Charlotte

Ty Consiglio

Amos

Kyle Breitkopf

Miles

James A Hughes

Henry

Ali Liebert

Ms. Petosa

Cameron Roberts

Cute Guy

Nadji Jeter

Justin

Ben Immanuel

Mr. Davenport

Jason McKinnon

School Photographer

Sônia Braga

Grans

Nicole Oliver

Jack Will's Mom

Emily Delahunty

Ximena Chin

Sasha Neuhaus

Maya

Rachel Hayward

Miranda's Mom

Grayson Maxwell Gurnsey

Our Town Player

Yan-Kay Crystal Lowe

Julian's Mom

Steve Bacic

Julian's Dad

Jason Tremblay

Camp Counsellor

Emma Tremblay

Michelle

Lidya Jewett

Lina Annan

Andre Robinson

School Kid (uncredited)