Hayley Mills

as Patti Randall

Dean Jones

as Zeke Kelso

Dorothy Provine

as Ingrid Randall

Roddy McDowall

as Gregory Benson

Frank Gorshin

as Iggy

Neville Brand

as Dan

Elsa Lanchester

as Mrs. MacDougall

William Demarest

as Mr. MacDougall

Richard Eastham

as Supervisor Newton

Grayson Hall

as Margaret Miller

Tom Lowell

as Canoe Henderson

Richard Deacon

as Drive-in-Manager

Iris Adrian

as Landlady

Liam Sullivan

as Graham

Don Dorrell

as Spires

Gene Blakely

as Cahill

Karl Held

as Kelly

Ed Wynn

as Mr. Hofstedder

Larry J. Blake

as Police Officer (uncredited)

John Cliff

as FBI Agent Hart (uncredited)

D.C. Benny

as Siamese Cat (uncredited)

Ben Lessy

as Drive-In Concessionaire (uncredited)