Javier Botet as Slender Man

Joey King as Wren

Julia Goldani Telles as Hallie

Jaz Sinclair as Chloe

Annalise Basso as Katie Jensen

Kevin Chapman as M. Jensen

Alex Fitzalan as Tom

Miguel Nascimento as Kyle

Michael Reilly Burke as Hallie's Dad

Jessica Blank as Hallie's Mom

Kayla Caulfield as High School Student

Jeffrey Corazzini as Police Officer

Michael Tow as Calculus Teacher

Adrian M. Mompoint as Jock

Danny Beaton as Burley Kid

Taylor Richardson as Lizzie

Kieran Tuomey as Student

Eddie Frateschi as Biology Teacher

Oscar Wahlberg as Boy with Glasses

Gabrielle Lorthe as Cheerleader

Marc Carver as Doctor

Kris Sidberry as Librarian

Angela Hope Smith as Nurse

Timothy Brierley as Tour Guide

Damon D'Amico Jr. as Student

Yohanna Perez as Student