1. L.B. "Jeff" Jefferies: Jeff is a professional photographer confined to his apartment with a broken leg. He spends his time observing his neighbors' activities through his rear window.
2. Lisa Fremont: Lisa is Jeff's girlfriend, a fashion model, and a frequent visitor to Jeff's apartment. She is initially skeptical of Jeff's suspicions about his neighbors but eventually comes to believe him.
3. Lars Thorwald: Lars is Jeff's neighbor, a traveling salesman, and the main suspect in Jeff's murder investigation. He is suspicious, secretive, and often seen carrying around a large trunk.
4. Stella Thorwald: Stella is Lars's wife and is portrayed as a fragile, submissive, and unhappy woman. She seems unaware of or unwilling to confront the suspicious activities of her husband.
5. Detective Thomas Doyle: Doyle is a police detective assigned to investigate Jeff's report about the suspected murder of Lars Thorwald. Initially, he does not believe Jeff's story, but as evidence accumulates, he begins to take the case more seriously.
6. Miss Lonelyhearts: Miss Lonelyhearts is a friendly but lonely neighbor living across the courtyard from Jeff's apartment. She is often seen caring for her small dog and has a crush on Lars Thorwald.