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 Strange

Monster

Laura Brook

Thelma (uncredited)

Adam Quintero

Mr. Gouldman (voice) (uncredited)