''Dial M for Murder'' is a 1954 thriller directed by Creator/AlfredHitchcock, based on a play by Frederick Knott, who also wrote the screenplay of the movie.

Retired tennis player Tony Wendice (Creator/RayMilland) discovers that his wealthy wife, Margot (Creator/GraceKelly) is cheating on him with crime author Mark Halliday (Robert Cummings). Tony decides to have her murdered, because he is the inheritor of her will, but if she would divorce him he'd lose her money. With a mixture of blackmail and reward, he gives the task to Swann (Anthony Dawson), an old classmate of his, whom he knows to be a crook. Tony creates a plan which he thinks to be perfect; however, things go wrong, when Margot manages to kill Swann. Tony, however, is able to use the situation to his own advantage, making things look as if Margot killed Swann because he was blackmailing her. It appears to be working, except Mark doesn't believe she's guilty and the police uncover a few anomalies...

''Dial M For Murder'' was [[UsefulNotes/ThreeDMovie filmed in 3D]], but by the time of its release, the 3D fad was dying out, so it had only a brief original release in 3D, followed by a conventional, "flat" release. Despite 3D being a gimmick, Hitchcock was able to employ it effectively, without too much distraction from the rest of the film.

The film was remade in 1998, with the title ''Film/APerfectMurder''.
!!This film provides examples of:

* AffablyEvil: Tony. He wants to get rid of his wife while continuing to enjoy her money, but he really doesn't hold a grudge against her for cheating on him. [[spoiler: Even after being exposed as the mastermind, he doesn't lost his friendly attitude and even offers the protagonists a drink, ''[[GracefulLoser with a smile]]'']].
* AssassinOutclassin: Margot turns the tables on her hired killer Swann and is able to stab him to death instead.
* BatmanGambit: Tony's plans.
* BlackCapOfDeath: Margot's trial scene ends with the horrified look on her face after the judge puts on his black cap.
* BlackmailIsSuchAnUglyWord:
-->'''Tony:''' I was hoping sooner or later I might catch you at something and be able to...
-->'''Swann:''' Blackmail me?
-->'''Tony:''' ''Influence'' you.
* BreakTheCutie: Poor, poor Margot. She's almost strangled, then convicted of murder and sentenced to death, then discovers her husband (for whom she had started to renew her love) was the one trying to kill her. By the end, she's surprised at how calm she is over all this, and Mark assures her she'll soon have "the most wonderful breakdown."
* ChekhovsGun: When Margot wants to go out at the night she's supposed to be killed, Tony persuades her to stay home instead, and finish pasting her newspaper clippings. She forgets to put away the scissors she uses for that, and eventually manages to stab Swann with them.
* ChekhovsArmory: Almost every single detail in the earlier scenes ends up affecting the course of the investigation.
* ColourCodedForYourConvenience: Margot wears bright colors at the start of the film, then progressively darker ones as time goes on. Even more, she is first seen in white with her husband, then red with her lover Mark.
* CreatorCameo: As usual for Hitchcock, but a particularly clever example--he is in the class reunion photo along with Swann and Tony.
* CurtainCamouflage: The killer hides behind the curtains.
* DutchAngle: Used when Swann is waiting at the desk and then concealing himself behind the curtain.
* FakingAndEntering: Type 2
* {{Foreshadowing}}: Mark says that if he tried to commit the perfect murder, he'd make some mistake and never realize it until everyone was looking at him. This is what happens to Tony.
* GracefulLoser: Tony. After a brief moment of shock when he's eventually caught, he calmly congratulates everyone and pours them some liquor.
* GoldDigger: Tony is a male example, as he married Margot for her money. She, however, as opposed to most {{Meal Ticket}}s is young and beautiful.
* ImprovisedWeapon: Margot stabs Swann with her scissors.
** And he was trying to strangle her with a scarf.
* TheJoyOfX: The title is frequently parodied.
* KeyUnderTheDoormat: The key under the staircase carpeting is a [[IncrediblyLamePun key]] plot point.
* KillingInSelfDefense: Margot manages to stab Swann while he's trying to strangle her.
* LadyInRed: Margot wears a sexy red dress when she meets with Mark.
* LaserGuidedKarma: [[spoiler: For all four main characters. Swann is a con-man who attempts murder, which gets him killed in self-defense. Margot starts out as a spoilt upper-class lady who cheats on his husband; she survives attempted murder and death row, but gets redemption in the end (and probably reparations for miscarriage of justice), and gets rid of Tony. Tony is rightfully indicted for having plotted the murder of his wife, and tried to set her up for murder. Though Mark has an affair with his friend's wife, he is the most honest character; he solves the case in the end, and will probably end up as Margot's companion.]]
* LingerieScene: Margot is in her nightgown when she's attacked. In the original script, she was to put a robe on, but Grace Kelly argued that a woman who thinks she's alone would have no reason to do that.
* MiscarriageOfJustice: Margot is found guilty and sentenced to death for the premeditated murder of Swann.
* OhCrap: The look on Tony's face when he turns on the lights and sees Mark, Margot, and Hubbard standing in the apartment is priceless.
* PaddleballShot: The famous shot where Kelly reaches out to the camera as she's being strangled (see the poster above) was originally a Paddleball Shot taking advantage of the 3-D.
* ThePerfectCrime: Tony wants to commit the perfect murder; he even asks Mark if he believes in it. Mark says that [[LampshadeHanging it's possible on paper, but not in real life]].
* PoliceAreUseless: One of Hitchcock's favorite tropes, but notably subverted here; the police officers at first seem to fall for Tony's manipulations and arrest Margot, but Chief Inspector Hubbard (John Williams) eventually solves the case. Near the film's climax, he even scolds Mark for nearly blowing the case.
-->'''Hubbard:''' They talk about flatfooted policemen. May the saints protect us from the gifted amateur.
* PrettyInMink: Margot wears a brown fur wrap for a date.
* ReverseWhodunnit: The audience knows from the beginning that Tony is behind everything.
* SarcasticConfession: Tony gets overconfident and makes the mistake of giving one to Hubbard.
* ShearMenace: Margot manages to kill Swann by stabbing him with a pair of scissors.
* ShoutOut: A clever little one to ''Film/StrangersOnATrain'' (which Hitch made three years before, in 1951), when Mark is talking about how he would plot the perfect murder, and he alludes to a possible scenario involving a tennis champ (like Tony--or like Guy in ''Strangers'').
* SpannerInTheWorks: Tony eventually fails, because he underestimates the intelligence of Swann.
* SpeechCentricWork: Most of the film consists of people talking. It was, after all, adapted from a stage play.
* TemptingFate: Tony literally guaranteeing to Swann that he faces no risk.
* ThisIsReality: Near the end, Mark is desperate to save Margot from being executed and comes to Tony with an idea he's worked out of how Tony could claim he had been trying to kill Margot and spend a few years in prison in exchange for saving her life. Unknowingly, he proceeds to outline almost the exact same plan that Tony actually used. Tony says that nobody would believe a story like that.
* VillainProtagonist: Tony.
* WronglyAccused: Due to Tony's manipulations, Margot is accused of murdering Swann for blackmailing her over her affair.
* XanatosSpeedChess: One of the great film examples, when Tony manages to turn Swann's death to his advantage.