Jacob Tremblay Auggie Pullman Julia Roberts Isabel Pullman Owen Wilson Nate Pullman Izabela Vidovic Via Pullman Noah Jupe Jack Will Millie Davis Summer Dawson Bryce Gheisar Julian Albans Mandy Patinkin Mr. Tushman Danielle Rose Russell Miranda Navas Daveed Diggs Mr. Browne Elle McKinnon Charlotte Cody Ali Liebert Ms. Petosa Nadji Jeter Justin Hollander Ty Consiglio Amos Conti Kyle Breitkopf Miles Noury James A Hughes Henry Joplin Nicole Oliver Mrs. Will Rachel Hayward Mrs. Navas Yan-Kay Crystal Lowe Melissa Albans Steve Bacic Julian Albans, Sr. Ben Immanuel Mr. Davenport Sônia Braga Grandma Emily Delahunty Ximena Chin Sasha Neuhaus Maya Markowitz Emma Tremblay Michelle Lidya Jewett Lina Annan Andre Robinson School Kid Jason Tremblay Camp Counsellor Mark Dozlaw Doogie Howser (uncredited)