The final girl is a horror film (particularly slasher film) trope that specifically refers to the last woman or girl alive to confront the killer, ostensibly the one left to tell the story. The final girl has been observed in dozens of films, including The Texas Chain Saw Massacre, Alien, Halloween, Scream, Friday the 13th, and A Nightmare on Elm Street. The term was coined  by Carol J. Clover in her book Men, Women and Chain Saws: Gender in the Modern Horror Film. Clover suggests that in these films, the viewer begins by sharing the perspective of the killer, but experiences a shift in identification to the final girl partway through the film.
According to Clover, the final girl is typically sexually unavailable or virginal, avoiding the vices of the victims (sex, narcotic usage, etc.). She sometimes has a unisex name (e.g. Teddy, Billie, Georgie, Sidney). Occasionally the Final Girl will have a shared history with the killer. The final girl is the "investigating consciousness" of the film, moving the narrative forward and as such, she exhibits intelligence, curiosity, and vigilance.
One of the basic premises of Clover’s theory is that audience identification is unstable and fluid across gender lines, particularly in the case of the slasher film. During the final girl’s confrontation with the killer, Clover argues, she becomes masculinized through "phallic appropriation" by taking up a weapon, such as a knife or chainsaw, against the killer. Conversely, Clover points out that the villain of slasher films is often a male whose masculinity, and exuality more generally, are in crisis. Examples would include Norman Bates in Alfred Hitchcock's Psycho, or Billy and Stu from Wes Craven's satirical horror film Scream. Clover points to this gender fluidity as demonstrating the impact of feminism in popular culture.
The phenomenon of the male audience having to identify with a young female character in an ostensibly male-oriented genre, usually associated with sadistic voyeurism, raises interesting questions about the nature of slasher films and their relationship with feminism. Clover argues that for a film to be successful, although the Final Girl is masculinized, it is necessary for this surviving character to be female, because she must experience abject terror, and many viewers would reject a film that showed abject terror on the part of a male. The terror has a purpose, in that the female is 'purged' if she survives, of undesirable characteristics, such as relentless pursuit of pleasure in her own right. An interesting feature of the genre is the 'punishment' of beauty and sexual availability.
The film Behind the Mask: The Rise of Leslie Vernon (2006) explains and talks extensively about this popular horror film trope (although in the film, it is referred to as "survivor girl"), even using it as a major plot device.
Examples of final girls
Before the release of Alien 3 Clover identified Ellen Ripley, from the Alien franchise, as a final girl. Elizabeth Ezra continues this analysis for Alien Resurrection, arguing that by definition both Ripley and Annalee Call must be final girls, further arguing that Call is the "next generation of Clover's Final Girl". Call, in Ezra's view, exhibits traits that fit Clover's definition of a final girl, namely that she is boyish, having a short masculine-style haircut, and that she is characterized by (in Clover's words) "smartness, gravity, competence in mechanical and other practical matters, and sexual reluctance" being a ship's mechanic who rejects the sexual advances made by male characters on the ship. Ezra notes, however, that this identification of Call as a final girl is marred by the fact that she is not a human being, but an android.
Christine Cornea disputes the idea that Ripley is a final girl, contrasting Clover's analysis of the character with that of Barbara Creed, who presents Ripley as "the reassuring face of womanhood". Cornea does not accept either Clover's or Creed's views on Ripley. Whilst she accepts Clover's general thesis of the final girl trope, she argues that Ripley does not follow the conventions of the slasher film, as Alien follows the different conventions of the science fiction film genre. In particular, there is not the foregrounding in Alien, as there is in the slasher film genre, of the character's sexual purity and abstinence relative to the other characters (who would be, in accordance with the final girl trope, killed by the film's monster "because" of this). The science fiction genre that Alien inhabits, according to Cornea, simply lacks this kind of sexual theme in the first place, it not having a place in such "traditional" sci-fi formats.
Laurie Strode (from Halloween I, II, and H20) is another example of a final girl. Tony Williams notes that Clover's image of supposedly progressive final girls are never entirely victorious at the culmination of a film nor do they manage to eschew the male order of things as Clover argues. He holds up Strode as an example of this. She is rescued by a male character, Dr. Loomis, at the end of Halloween. He holds up Lila Crane, from Psycho, as another example of a final girl who is saved by a male (Sam, in this case) at the end of the film. On this basis he argues that whilst 1980s horror film heroines were more progressive than those of earlier decades, the gender change is done conservatively, and the final girl trope cannot be regarded as a progressive one "without more thorough investigation".
Williams also gives several examples of final girls from the Friday the 13th franchise: Alice from Friday the 13th, and the heroines from Part II and Part III. (He observes that Friday the 13th: The Final Chapter does not have a final girl.) He notes that they do not conclude the films wholly victorious, however. The heroines from Parts II and III are catatonic at the ends of the respective films, and Alice survives the monster in the first film only to fall victim to "him" in the second. The final girl in Part III is carried away on a stretcher, calling out for her boyfriend (which Williams argues again undermines the notion of final girls always being victorious). Moreover, Ginny's adoption of the monster's own strategy, in Part II, brings into question whether the final girl image is in fact a wholly positive one.
Mary Celeste Kearney observes that in the middle 1990s, the trope of the final girl in horror films was "resurrected, reshaped, and mainstreamed". She points to Sidney Prescott (in Scream I, II, and III) and Julie James (in I Know What You Did Last Summer and I Still Know What You Did Last Summer) as examples of this.