Sylvia Sidney as Mrs. Verloc

Oskar Homolka as Karl Verloc - Her Husband

Desmond Tester as Stevie - Her Young Brother

John Loder as Ted

Joyce Barbour as Renee

Matthew Boulton as Superintendent Talbot

S. J. Warmington as Hollingshead

William Dewhurst as The Professor

Clare Greet as Mrs. Jones (uncredited)

Aubrey Mather as Greengrocer (uncredited)

Austin Trevor as Monocle Man (uncredited)

Charles Hawtrey as Studious Youngster (uncredited)

Martita Hunt as The Professor's Daughter (uncredited)

Torin Thatcher as Mr. Verloc's Visitor (uncredited)

Peter Bull as Mr. Verloc's Visitor (uncredited)

Alfred Hitchcock as Man Walking Past the Cinema as the Light Is Renewed