Mickey Rooney as Timothy Dennis

Edmund Gwenn as Headmaster Justin

Ian Hunter as Roger Carlton

Freddie Bartholomew as Peter Carlton

Marta Linden as Winifred Dennis Carlton

Juanita Quigley as Jane 'The Runt' Dennis

Alan Mowbray as Mr. Duncan

Peter Lawford as Ronnie Kenvil

Raymond Severn as 'Inky' Weeld

Harry Duff as Eton Student (uncredited)

Robert Lynn as Eton Student (uncredited)

Tina Thayer as Flossie Sampson (uncredited)