 | Carroll Baker Sylvia: West (Karoki, Kay, Carlyle) |
 | George Maharis Alan Macklin |
 | Joanne Dru Jane (Bronson) Phillips |
 | Peter Lawford Frederic Summers |
 | Viveca Lindfors Irma Olanski |
 | Edmond O'Brien Oscar Stewart |
 | Aldo Ray Jonas Karoki |
 | Ann Sothern Mrs. Argona / Grace Argona |
 | Lloyd Bochner Bruce Stamford III |
 | Paul Gilbert Lola Diamond |
 | Jay Novello Father Gonzales |
 | Nancy Kovack Big Shirley |
 | Gene Lyons Gavin Cullen |
 | Anthony Caruso Wilbur (aka "Muscles") |
 | Alan Carney Gus |
 | Shirley O'Hara Mrs. Karoki |
 | Ricky Allen Herbert, the Boy in the Library (uncredited) |
 | Val Avery Pudgey Smith (uncredited) |
 | Majel Barrett Anne (uncredited) |
 | Jean Del Val Maitre'd (uncredited) |
 | Connie Gilchrist Molly Banter (uncredited) |
 | Gavin Gordon Butler (uncredited) |
| Clive Halliday Calligraphy Professor (uncredited) |
 | John Harmon Sid (uncredited) |
 | Stacy Harris Mr. Leland (uncredited) |
| Kathleen Mulqueen Assistant Principal (uncredited) |
 | Manuel Padilla Jr. Pancho Guzman (uncredited) |
 | Robert Random (uncredited) |
 | Gene Roth Professor Eglebert (uncredited) |
 | Geraldine Wall Clerk at Private Hospital (uncredited) |
 | Paul Wexler Peter Memel (uncredited) |
| Sound | |
| David Raksin | Music |
Directing | |
| Gordon Douglas | Director |
Writing | |
| Sydney Boehm | Screenplay |
| Howard Fast | Screenplay |
Costume & Make-Up | |
| Joan Joseff | Other |
Crew | |
| Joseph Ruttenberg | Cinematography |
Sound | |
| John Wilkinson | Sound Recordist |
| Harry Lindgren | Sound Recordist |
Production | |
| Shirley Mellner | Associate Producer |
Art | |
| Arthur Krams | Set Decoration |
Editing | |
| Frank Bracht | Editor |
Costume & Make-Up | |
| Wally Westmore | Makeup Supervisor |
Crew | |
| Paul K. Lerpae | Special Effects |
Costume & Make-Up | |
| Edith Head | Costume Design |
Sound | |
| Van Cleave | Orchestrator |
Directing | |
| Dick Moder | Assistant Director |
Production | |
| Martin Poll | Producer |
Art | |
| Sam Comer | Set Decoration |
Visual Effects | |
| Farciot Edouart | Visual Effects |
Sound | |
| Paul Anka | Theme Song Performance |
| Edward B. Powell | Orchestrator |
Production | |
| Steve Shagan | Associate Producer |
Art | |
| Hal Pereira | Art Direction |
| Roland Anderson | Art Direction |
Sound | |
| Howard Beals | Sound Editor |
Costume & Make-Up | |
| Nellie Manley | Hair Supervisor |
