Jeremy Ray Taylor

Sonny Quinn

Madison Iseman

Sarah Quinn

Caleel Harris

Sam Carter

Wendi McLendon-Covey

Kathy Quinn

Ken Jeong

Mr. Chu

Chris Parnell

Walter

Bryce Cass

Tyler

Peyton Wich

Tommy Madigan

Shari Headley

Mrs. Carter

Christian Finlayson

Cooper

Matthew J. Vasquez

Derek

Courtney Lauren Cummings

Jess

Jessi Goei

Maya

Drew Scheid

Tyler's Crew

Sydney Bullock

Vanessa

Jason Looney

Terrified Parent Monster-Mr. Rennie

Kendrick Cross

Sam's Father

Déjá Dee

Mrs. Hoover

Brick Jackson

Paramedic- TJ

R.L. Stine

Science Award Presenter-Principal Harrison

Mick Wingert

Slappy (voice)

Jack Black

R. L. Stine (uncredited)

Jasmine Bolton

Middle School Kid (uncredited)

Darin De Paul

Terry / Angry Pumpkin (voice) (uncredited)

Suehyla El-Attar Young

Teacher in Hole (uncredited)

Catherine Jerald

Monster (uncredited)

Sawyer D. Jones

Trick-or-Treater (uncredited)

Gracie Marcellus

Middle Schooler (uncredited)

Shaun McMillan

Middle School Principal (uncredited)

Ivy O'Brien

(uncredited)