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 HBO Max.
| Production | Hilton A. Green | Producer |
| Sound | Carter Burwell | Original Music Composer |
| Camera | Bruce Surtees | Director of Photography |
| Writing | Charles Edward Pogue | Screenplay |
| Directing | Anthony Perkins | Director |
| Editing | David E. Blewitt | Editor |
| Production | Nancy Nayor | Casting |
| Costume & Make-Up | Marla Schlom | Costume Design |
| Sound | Roger Heman Jr. | Sound Re-Recording Mixer |
| Sound | Michael C. Casper | Sound Re-Recording Mixer |
| Costume & Make-Up | Peter V. Saldutti | Costume Design |
| Sound | Jeffrey Wilhoit | Foley |
| Crew | Louis R. Cooper | Special Effects |
| Directing | Betty A. Griffin | Script Supervisor |
| Production | Booker McClay | Publicist |
| Costume & Make-Up | Vivian McAteer | Hairstylist |
| Sound | John J. Stephens | Sound Re-Recording Mixer |
| Crew | Michael Westmore | Makeup Effects |
| Camera | Rick Neff | Camera Operator |
| Camera | Michael Dugan | Underwater Camera |
| Art | Henry Bumstead | Production Design |
| Art | Mickey S. Michaels | Set Decoration |
| Crew | Karl G. Miller | Special Effects |
| Costume & Make-Up | Liza Stewart | Set Costumer |
| Crew | Danny Lester | Special Effects |
| Costume & Make-Up | Mark Reedall | Makeup Artist |
| Sound | John Stacy | Supervising Sound Editor |
| Crew | Bob Yerkes | Stunt Coordinator |
| Visual Effects | Syd Dutton | Visual Effects |
| Costume & Make-Up | Brian O'Dowd | Set Costumer |
| Camera | Christine M. Loss | Still Photographer |
| Writing | Robert Bloch | Original Story |
| Production | Don Zepfel | Associate Producer |
| Sound | James Thompson | Sound Recordist |
