George MacKay
Jack Marrowbone
Anya Taylor-Joy
Allie
Charlie Heaton
Billy Marrowbone
Mia Goth
Jane Marrowbone
Matthew Stagg
Sam Marrowbone
Nicola Harrison
Rose Marrowbone, Mother
Kyle Soller
Tom Porter
Tom Fisher
Simon Fairbairn, Father
Myra Kathryn Pearse
Molly
Paul Jesson
Doctor
Robert Nairne
Monster
Laura Brook
Thelma (uncredited)
Adam Quintero
Mr. Gouldman (voice) (uncredited)