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)