Played By: Anthony Perkins (the whole film series), Henry Thomas (Young Norman in Psycho IV), Vince Vaughn (in Psycho 1998)
- Adorkable: An awkward, shy momma's boy...at first.
- Affably Evil: When running a motel, one needs to be a people person.
- Anti-Villain: As he notes during his conversation with Marion Crane on private traps, "I was born into mine. I don't mind it anymore".
- Ax-Crazy: When the mother side of his personality is in control, brutally stabbing anyone she needs to kill over and over again.
- Bad Liar: Although surprisingly enough, his stuttering and incessant chewing goes some way in convincing Arbogast that he had nothing to do with Marion's disappearance.
- Being Evil Sucks: For the Norman personality, going through extreme amounts of stress and anxiety covering up the murders, as well as dealing with his guilty conscience.
- Cartwright Curse: Connie (from Psycho IV) is the only one of Norman's love interests who escapes a tragic fate.
- Creepy Crossdresser: When his mother personality takes over.
- Cute and Psycho: Rare male example. His boyish charm and poor social skills can easily throw off the viewer as to his true nature.
- A Date with Rosie Palms: Subtly implied in the original, and flat out shown in the remake.
- Dark and Troubled Past: Father died when he was five years old, leaving him in the care of an overbearing and somewhat incestuously inclined mother, who would emotionally abuse and degrade him.
- Doom Magnet: All of his love interests die as a result of getting too close to him.
- Driven to Madness: By his domineering mother, no less.
- Driven to Villainy: When his mother takes a lover and continues in bullying him.
- Extreme Doormat: To his mother, who deliberately made him dependent upon her after his father's death.
- Freudian Excuse: The abuse he was subject to by his mother when he was young.
- Gollum Made Me Do It: The last scene of the film is his mother personality plotting and scheming to blame Norman for the murders.
- Hidden Depths: He's shown to be somewhat of a nihilistic philosopher during his brief interactions with Marion Crane.
- Knife Nut: As his mother. All of the murders are committed with a large kitchen knife.
- Kubrick Stare: Perhaps the most grim and soul destroying one in cinematic history.
- Momma's Boy: "A boy's best friend is his mother."
- Mommy Issues: His murderous split personality is due to being emotionally dependent upon his mother since his father died at five years old.
- Nice Guy: When Mommy doesn't take over...
- Oedipus Complex: Norman's mother deliberately isolated her five-year-old son from the outside world and made him utterly dependent on her after Mr Bates' death. Naturally enough, the twelve-year-old, completely co-dependent Norman then reacted rather badly to her remarriage.
- The Peeping Tom: In the parlor and hidden behind a painting, is a hole that looks into Cabin 1. He uses it to look at Marion Crane and Maureen Coyle.
- Reluctant Psycho: In Psycho II, Psycho III and Psycho IV.
- Serial Killer: In Psycho II, he is revealed to have killed seven people before being captured at the end of the first film.
- Sex Is Evil and I Am Horny: When Norman finds himself attracted to women (such as Marion Crane), the "mother" side of his personality lashes out and seeks to rid him of his sinful urges by way of murder.
- Split Personality: Norman and his internalized mother.
- Split Personality Takeover: At the end of the first film. In the words of the psychiatrist: "Norman Bates no longer exists". He gets better in the sequel, however.
- Sweet Tooth: He's frequently seen with a bag of candy.
- Taxidermy Is Creepy: He keeps a roomful of stuffed birds adjacent to the motel office. And the film's great twist is that his "mother" is actually just a preserved and stuffed corpse.
- Tragic Villain: Although one with an ultimately happy ending, provided you see Psycho IV as being canon.
- Villain Protagonist: After Marion's death, the film rotates between him and her sister as primary protagonists.
- Wicked Cultured: Norman is devotee of Beethoven. While searching his room in the first film Lila notes a record of Symphony No. 3 ("Eroica") on his turntable, and in Psycho II he plays the Moonlight Sonata on the piano.
Played By: Janet Leigh (in Psycho 1960), Anne Heche (in Psycho 1998)
- Decoy Protagonist: The Trope Codifier. While Sam and Norman both get a decent amount of screen-time in the early stages, the film is almost entirely her story. Then the shower scene happens...
- Redemption Equals Death: She would likely have ended up dead either way, but after having dinner with Norman (and just before her fatal shower) she decides to return the stolen money to her employers and face the music.
- Sacrificial Lion: Most famously, the film spends the first half detailing her motivations and conflicts, to make it more horrifying when Norman slaughters her.
- Stealing from the Till: Her primary conflict is stealing money from her place of business to help pay off her lover's debts.
Lila Loomis, née Crane
Played By: Vera Miles (in Psycho 1960 and Psycho II), Julianne Moore (in Psycho 1998)
- Asshole Victim: In Psycho II, her actions in the sequel before her death might have been good intentioned in a way, but otherwise still amoral and vindictive towards a man who paid his debt to society.
- Cruel and Unusual Death: Impaled through the mouth with a kitchen knife in Psycho II.
- Gone Horribly Right: Her plan to drive Norman insane again in the second film goes off very well. Unfortunately, she wasn't counting on Mary becoming sympathetic towards Norman, and definitely didn't foresee Emma Spool messing everything up.
- Hero Antagonist: Towards Norman, in Psycho and Psycho II, however, it's subverted in Psycho II, as the Antagonist side of this trope outweigh the Hero part despite Lila still fulfilling the same trope.
- Inspector Javert: A non-cop version. Still hounds Norman and views him as the irredeemable murderer after he's been released from the mental institution in Psycho II.
- Jerkass Has a Point: In Psycho II, although she does not give Norman a chance for the murder of her sister, in the opening courtroom scene, she was correct that usually the justice system would not give criminals convicted of first degree murder a light sentence of being released back into society to reintegrate, which is why Lila in the second film counts as a Well-Intentioned Extremist.
- Not So Different:
- Seeing as how Lila treats her daughter in Psycho II, she has more than a few similarities to the mother that drove Norman Bates insane.
- And, of course, there's the fact that she sets everything up to make Norman go insane again. Sure, she has a reason for not liking him because he killed her sister and several other people, but to attempt to send him back to the asylum and possibly kill again is just wrong.
- Relationship Upgrade: She married Sam Loomis between Psycho and Psycho II.
- She Who Fights Monsters: In Psycho II. Her obsession to avenge the death of her sister against her murderer slowly begins to corrupt her, causing her to Took a Level in Jerkass by being amoral in her actions and even allowing murders not committed by Norman to be pinned on him anyway.
- Took a Level in Jerkass: In Psycho II. In the first movie, she was a polite but determined woman who wanted to find out what happened to her sister. In Psycho II she tries to amorally drive Norman insane again out of revenge.
- Vigilante Woman: In Psycho II, when she decides to take the law to her own hands to apprehend Norman herself after feeling the courts "protect criminals, not their victims," when Norman was released and declared sane.
- Well-Intentioned Extremist: In Psycho II. Aside from the fact that her attempts to drive Norman insane again to get him recommitted are a result of avenging her sister's death, it also seems out of protecting any other potential victims (or as she quotes them to be "an innocent public") out of harm's way of a "homicidal maniac" (also quoted by her in the opening courtroom scene) in case if he ever relapsed back into insanity on his own without any interference from outside parties such as herself if not sooner. Plus, even though Lila did not seem to care if others who are already killed to have their deaths pinned on Norman anyway, it could be possible Lila saw them as necessary Sacrificial Lambs to bring, what she see it as, a Karma Houdini murderer to justice.
- Widow Woman: In Psycho II, where it's revealed Sam Loomis, whom she married after the events of the first film, has died before the events of the second film.
Norma Bates, née Spool
Played By: Olivia Hussey (in Psycho IV)
- Evil Matriarch: Though ''Psycho IV downplays this.
- Manipulative Bitch: Even beyond the grave she continues to torment Norman.
- Mummies at the Dinner Table: In Psycho. Norman preserves her corpse as best he can and keeps her in the master bedroom, hiding her in the fruit cellar when anyone comes snooping around.
- My Beloved Smother: Part of Norman's backstory is that she dominated him and forced him to become co-dependent after his father died. Not to mention her bullying behavior during the film. Or at least, her behavior as Norman remembers her, anyway.
- The Unseen: She's never seen until the end of Psycho. But she is often heard either by Norman or anyone not near the two in the first movie.
Mary Samuels (real name Loomis)
Played By: Meg Tilly (in Psycho II)
- Dead Person Impersonation: Impersonates Norman's mother with a robe, a wig and the kitchen knife in hope of stopping him from going insane again. It doesn't end well for her.
- Heel-Face Turn: She grows genuinely convinced of Norman's newfound sanity and at some point doesn't want to help her mother make him insane anymore, however, after discovering Lila's dead body, she fully accept Lila was right all along about Norman and gets killed just after believing into it.
- Hero Antagonist: Was in on Lila's plan to bring Norman to justice and have him incarcerated for good. Subverted when she starts to sympathize with Norman and later turn against her mother's intentions to have him arrested again. However, after discovering Lila's body in the pile of coal in Norman's cellar, Mary firmly grasped completely on this trope only to seconds later be shot by the police for her attempt on Norman's life.
- Kill the Cutie: She is shot dead by the police after an unlucky and tragic chain of reactions.
- Sympathetic Inspector Antagonist: In contrast her mother's Inspector Javert, Mary, despite being in on her mother's plans, is sympathetic towards Norman and later turn against her mother's mission to have Norman re-arrested and re-committed, until seeing her mother's corpse convinces her Lila was right all along it seems.
- Vigilante Woman: At first, she was involved with her mother's Well-Intentioned Extremist plans, but later turn against Lila after becoming convinced of Norman's newfound sanity, but later plays this role straight for a minute in the climax after discovering her mother's dead body.
Played by: Diana Scarwid (in Psycho III)
- Kill the Cutie: By accident. Or was it Mother's spirit?
Played by: Claudia Bryar (in Psycho II)
- Bigger Bad: Of the original trilogy, through kidnapping Norman as a baby and killing Norman's biological dad, she's indirectly responsible for her sister to abuse Norman that turned him into a serial killer that lead to the events of the first film and its sequels.
- Knife Nut: She is the knife-wielding murderer in Psycho II.
- Mummies at the Dinner Table: "Replaces" Norman's mother at the end of Psycho II and in Psycho III. Norman stuffs her body at the beginning of Psycho III.
- Parental Substitute: Sort of. In the most horrible way imaginable actually. She "replaces" Norman's mother as a mummy Norman talks to.
- The Reveal: She is Norma's sister.