The Pink Panther refers to a gem in the first movie, not Inspector Clouseau, like some people think. It also doesn't refer to the popular animated pink panther features in an animated series and commercials for Owens-Corning insulation. The sequels largely turned the Pink Panther into an Artifact Title, with only some of the sequels actually featuring the gem in any capacity.
The title of the film The Last Samurai actually refers to the entire group of fighters at the end of the movie, but Japanese nouns are both plural and singular. Thus, many think it refers exclusively to Tom Cruise's character, especially given that he is the only one to survive. This misinterpretation crept into at least one international translation of the title, in a language that does make a distinction between singular and plural for "samurai".
The title of Highlander refers to Connor (and later Duncan) McLeod's origin as a Scottish Highlander, not to the race of immortals (who are simply call that, "Immortals") that he turns out to be part of.
The "Thin Man" referred to in the title of the first The Thin Man film refers to the victim, but is often erroneously assumed to refer to Nick Charles, one of the heroes. The sequels included references to "the Thin Man" in their titles to use the misconception to help brand the series.
Ratatouille is simply a cute pun for the title of the film, and the featured dish at the film's climax, not the name of any of the rats actually in the movie. The main rat character is named Rémy.
The woman from Chasing Amy is named Alyssa. Amy is Silent Bob's ex, whom he brings up to draw parallels to the main character's relationship with Alyssa.
Many people believe that the title character of The Big Lebowski is that played by Jeff Bridges. The plot is driven by a case of mistaken identity between Bridges' character and another character also named Jeffrey Lebowski. However, Bridges' character repeatedly insists that he is properly called "the Dude," and refers to the other man as "the big Lebowski" several times throughout the film.
The eponymous whale of the film Free Willy was not named "Free Willy". The whale was named simply Willy; the title comes from a scene where Jesse says "let's free Willy!" It doesn't help that the sequels used "Free Willy" in their titles.
The main character in Ong Bak is called Ting. Ong-Bak is a Buddha statue in his village temple.
Jaws is not the name of the shark in the movies of the same name. The shark doesn't have a name at all, although on the set the mechanical shark used for filming was referred to as "Bruce", after Spielberg's lawyer.
The Dog-Thing from The Thing (1982) is not named "Jed", and neither is "the Norwegian sled dog". Jed is the name of the wolf-dog who played the Norwegian sled dog. "Jed" and "Jed-Thing" are fan names given to the character and creature because it's less of a mouthful than "Norwegian sled dog" and "Norwegian sled dog-Thing". It may also be a reference to the fact that John Carpenter and Kurt Russell simply refer to the dog as Jed in the DVD commentary.
The creatures from the movie (and television series) Tremors are called "Graboids". So many viewers have called the creatures "Tremors" that this has been brought into the series; at one point a tourist mentions a "tremor", prompting a main character to exclaim in exasperation, "They're called Graboids!"
The flying alien monsters in Pitch Black remain nameless throughout the film. Sorry, "bio-raptor" and "demon" are just fanspeak.
Likewise, "Xenomorph" (literally: "alien form") was used as a placeholder term to refer to the then-unclassified Aliens, but the species is never actually named in the films. "Xenomorph" is purely a fan term for convenience's sake, since "the aliens from Aliens" is too clunky to use in discussion.
The title character of Local Hero is never explicitly stated. Mac, the main character, is not local nor particularly heroic, but he does help get the right people together to save the town and the whole point of the film is how he becomes a part of the town by the end, in spite of leaving for home. The soundtrack song titles do refer to him as a local hero. However, many people feel that the Ben, the old beach bum who stands against the oil company and convinces the company's CEO to drill elsewhere is the local hero, is the more clear candidate, since he's both local and a hero.
Comic Book The Movie features an in-universe example of the trope's title example: a woman is condescendingly corrected by her four year old that the action figure his father has just bought is Captain Marvel, not Shazam.
In Disney's Sleeping Beauty, the princess' name is Aurora, but never actually "Sleeping Beauty", which is a title of sorts.
In Bride Of Re Animator, the eponymous Bride is being constructed for Herbert West's heartbroken assistant, not for Herbert West the Re-Animator himself.
In all three versions of the movie, King Kong is the show name for the giant gorilla when he is brought back to New York — his real name is just "Kong". The same thing goes for the "Mighty" part of Mighty Joe Young; the character also being referred to as "Mr. Joseph Young", or "Joe" (in the remake, it's just "Joe").
A strange inversion: while Ichi the Killer is the name of the main character in the film, the character who appears predominantly on the posters, DVD covers, and other promotional images is actually the antagonist Kakihara, who is often mistaken for Ichi.
The monster in Cloverfield is not named Cloverfield. It was called "Clover" in film production and "LSA" for "Large-Scale Aggressor" by the military in the film.
Pop culture osmosis of the Boris Karloff version of Frankenstein 1931 is what brought the masses to assume that the creature is called Frankenstein rather than the scientist who creates him. The creature has no name, but is commonly called "Frankenstein's monster." He's never referred to as a "monster" in the original novel. He's referred to as a "creature," and Mary Shelley also referred to him as "Adam."
Johnny Mnemonic is not the name of its main character - he's just Johnny. Or "Just Johnny."
An interesting in-movie example occurs in Destroy All Monsters. During one scene, when all the monsters are attacking various cities, a news reporter claims that Baragon is attacking Paris, France. The problem? That's not Baragon attacking Paris but rather Gorosaurus. Interestingly enough, Toho did originally want to use Baragon in the scene, but the suit was too badly damaged so they used Gorosaurus instead. Though, why they still mistakenly referred to Gorosaurus as "Baragon" is unknown.
In the Zatoichi series, the protagonist's name is Ichi, Zato refers to a historical guild for blind men. Ichi should be called Zato-no-Ichi, but this is shortened to Zatoichi
Yojimbo means bodyguard. While the character is No Name Given, he identifies himself as Sanjuro. Zatoichi Meets Yojimbo gets double points for this (since "Zatoichi" is actually named Ichi), although kind of justified in that while Mifune is obviously playing the same character as he did in the two Kurosawa films, for legal reasons, he's called something else.
Whenever Mel Gibson's portrayal of William Wallace in Braveheart is spoofed, odds are he'll get called "Braveheart" rather than Wallace.
Sean Connery's character in Zardoz is Zed, not Zardoz. Zardoz actually is The Wonderful WiZARDofOZ.
The General is the train, not Buster Keaton's character. In fact, Johnnie Gray is only shown enlisted to be a lieutenant at the end.
Similar to the above: many people think that Saw is the name of the main villain, or even of the puppet appearing in the film, becoming a sort of mascot for the series. The puppet is named Billy, and the name given by the press to the killer is Jigsaw.
The main character of Kikujiro no Natsu is not named Kikujiro. We don't know who it is before the ending, which is a simple but brillant twist. Even if the DVD case may tell you who it is actually.
The movie Breakfast at Tiffany's has the same problem as the book with people thinking Tiffany is the main character, instead of a company. Holly Golightly is the name of the main character.
The name of the main antagonist in Men in Black is "The Bug", not "Edgar". Edgar is the name of the farmer whom the Bug kills and disguises himself as. (Oddly enough, action figures and even the cartoon spin-off refer to the Bug as "Edgar").
The Mexican refers to the name of the legendary gun at the heart of the story and is not referring to Brad Pitt's character.
Benny & Joon does not refer to the romantic leads, but the brother and sister. Johnny Depp is NOT the titular Benny (his character is named Sam), but this mistake is made often.
People who are not familiar with the film tend to assume that David Bowie's character is the eponymous "Mr. Lawrence" in Merry Christmas, Mr. Lawrence. Bowie's character is in fact called Captain Jack Celliers. Mr. Lawrence is another POW, the camp's translator and the only surviving member of the main cast at the end of the film.
The villain in Wishmaster is sometimes referred to as being "Wishmaster" by people describing the film. The villain is not called Wishmaster; that's just a role he fulfills. He's the Djinn.