When Maureen Coyle, a suicidal nun who resembles Norman's former victim, Marion Crane, arrives at the motel, all bets are off and "Mother" is less than happy.
Unfortunately the movie Psycho III is not yet available on Disney Plus.
| Production | Hilton A. Green | Producer |
| Camera | Bruce Surtees | Director of Photography |
| Writing | Charles Edward Pogue | Screenplay |
| Sound | Carter Burwell | Original Music Composer |
| Directing | Anthony Perkins | Director |
| Editing | David E. Blewitt | Editor |
| Crew | Michael Westmore | Makeup Effects |
| Sound | Michael C. Casper | Sound Re-Recording Mixer |
| Costume & Make-Up | Liza Stewart | Set Costumer |
| Costume & Make-Up | Mark Reedall | Makeup Artist |
| Sound | Jeffrey Wilhoit | Foley |
| Production | Nancy Nayor | Casting |
| Costume & Make-Up | Marla Schlom | Costume Design |
| Sound | Roger Heman Jr. | Sound Re-Recording Mixer |
| Sound | John J. Stephens | Sound Re-Recording Mixer |
| Visual Effects | Syd Dutton | Visual Effects |
| Art | Mickey S. Michaels | Set Decoration |
| Costume & Make-Up | Peter V. Saldutti | Costume Design |
| Costume & Make-Up | Vivian McAteer | Hairstylist |
| Crew | Danny Lester | Special Effects |
| Art | Henry Bumstead | Production Design |
| Costume & Make-Up | Brian O'Dowd | Set Costumer |
| Sound | John Stacy | Supervising Sound Editor |
| Camera | Michael Dugan | Underwater Camera |
| Crew | Karl G. Miller | Special Effects |
| Crew | Louis R. Cooper | Special Effects |
| Production | Booker McClay | Publicist |
| Camera | Christine M. Loss | Still Photographer |
| Crew | Bob Yerkes | Stunt Coordinator |
| Camera | Rick Neff | Camera Operator |
| Directing | Betty A. Griffin | Script Supervisor |
| Writing | Robert Bloch | Original Story |
| Production | Don Zepfel | Associate Producer |
| Sound | James Thompson | Sound Recordist |
