Dwayne Johnson as Dr. Smolder Bravestone

Kevin Hart as Franklin 'Mouse' Finbar

Jack Black as Professor Sheldon 'Shelly' Oberon

Karen Gillan as Ruby Roundhouse

Rhys Darby as Nigel Billingsley

Bobby Cannavale as Van Pelt

Nick Jonas as Jefferson 'Seaplane' McDonough

Alex Wolff as Spencer Gilpin

Ser'Darius Blain as Anthony 'Fridge' Johnson

Madison Iseman as Bethany Walker

Morgan Turner as Martha Kaply

Sean Buxton as Jogger

Mason Guccione as Gamer

Marin Hinkle as Spencer's Mom

Tracey Bonner as Fridge's Mom

Najah Jackson as Girl in Car

Natasha Charles Parker as Bethany's Mom

Kat Altman as Lucinda

Maribeth Monroe as Teacher

Missi Pyle as Coach Webb

Michael Shacket as Fussfeld

Jamie Renell as Male Gym Teacher

Marc Evan Jackson as Principal Bentley

Carlease Burke as Miss Mathers

Jason New as Bivouac Biker

Rohan Chand as Kid at Bazaar

William Tokarsky as Bread Vendor

Tait Fletcher as Scorpion Recipient

Stephen Dunlevy as Transportation Shed Guard

Rob Mars as Transportation Shed Guard

Colin Hanks as Alex Vreeke (uncredited)

Virginia Newcomb as Alex's Wife (uncredited)

Sylvia Jefferies as Jogger's Wife (uncredited)

Daniel Salyers as High School Student (uncredited)

Tim Matheson as Old Man Vreeke (uncredited)

Tad Sallee as Skater Punk (uncredited)

Ryan Baughman as Boy #1 (uncredited)

Maddie Nichols as Kid #2 (uncredited)

Ashley Lonardo as Kid #3 (uncredited)

Friday Chamberlain as Amazon Warrior (uncredited)

Ted Williams as Gypsy Cowboy (uncredited)

Juan Gaspard as The Spy (uncredited)

Scott Hunter as Van Pelt's Henchman (uncredited)

Maiya Boyd as Cute Bazaar Kid (uncredited)

Natasha Mayet as Berber Lady (uncredited)

Danny Pardo as Bazaar Vendor (uncredited)