Friday the 13th: The Final Chapter is a 1984 American slasher film directed by Joseph Zito, produced by Frank Mancuso Jr., and starring Kimberly Beck, Corey Feldman, Crispin Glover, and Peter Barton. It is the sequel to Friday the 13th Part III (1982) and the fourth installment in the Friday the 13th franchise. Picking up immediately after the events of the previous film, the plot follows a presumed-dead Jason Voorhees (Ted White) who escapes from the morgue and returns to Crystal Lake to continue his killing spree. The film marks the debut of the character Tommy Jarvis (Feldman), who would make further appearances in two sequels and related media, establishing him as Jason's archenemy.

Much like Part III, the film was originally supposed to be the final installment. Mancuso Jr. wanted to conclude the series as he felt no one respected him for his producing work on it regardless of how much the films earned at the box office, while also wanting to pursue other projects. Paramount Pictures supported the decision, as they were aware of the declining popularity of slasher films at the time of its release. As a result, the film was billed as The Final Chapter to ensure it as such. Make-up artist Tom Savini, who worked on the first installment, returned because he wanted to help kill off Jason, whom he helped create.

The film was originally scheduled to be released in October but was pushed up to April 13, 1984. Upon its theatrical release, it grossed $33 million in the U.S. on a budget of $2.2 million, making it the fourth most attended of the Friday the 13th series with approximately 9,815,700 tickets sold. Though the film received negative reviews from critics at the time of release, it has retrospectively come to be considered one of the stronger entries in the series. Despite being billed as the final entry, its success prompted another sequel, Friday the 13th: A New Beginning, one year later, followed by a further six sequels, a reboot and a prequel television series.

Following the murders at Higgins Haven, police clean up the grounds and Jason Voorhees' body, believed to be dead, is taken to the morgue. The hockey masked killer spontaneously revives and escapes from the cold storage at the hospital, murdering the coroner Axel Burns with a hacksaw and gutting Nurse Robbie Morgan with a scalpel. The following day, a group of teenagers drives to Crystal Lake for a summer trip. The group comprises Paul, his girlfriend Samantha, virgin Sara, her boyfriend Doug, awkward Jimmy, and jokester Ted. On the way, the group comes across Pamela Voorhees' tombstone and a hitchhiker, whom Jason soon kills.

Next door to the teens' rental house is the Jarvis family, consisting of Trish, her twelve-year-old brother Tommy, their mother and the family dog Gordon. While going for a walk the next day, the teens meet twin sisters Tina and Terri and go skinny dipping with them. Trish and Tommy happen upon the scene, and Trish is invited to a party taking place that night. Afterward, when their car breaks down, Trish and Tommy are helped out by a young man named Rob Dier. They take him to their house, where Tommy shows him several monster masks he made before Rob leaves to go camping.

Later that night, the teens begin the party. A jealous Sam sees Tina flirting with Paul and leaves. She goes out to the lake, where Jason impales her from under a raft. When Paul goes out to look for her, he is harpooned in the crotch. Terri decides to leave the party early, but Jason stabs her with a spear before she can get on her bike. Next door, Mrs. Jarvis arrives home and discovers the power is out. While searching for her children and Gordon, she is killed offscreen. Trish and Tommy soon arrive and realize their mother is missing. Trish goes to search for her and finds Rob's campsite. He explains to her that he is the brother of Sandra Dier, a teenager who was recently murdered by Jason, and reveals that Jason is still alive and that he came to Crystal Lake to avenge his sister's death. Worried about Tommy's safety, Trish and Rob return to the house.

After sleeping with Tina, Jimmy goes downstairs to get a bottle of wine only for Jason to pin his hand down with a corkscrew and strike his face with a cleaver. Upstairs, Tina looks out a window and finds that Terri's bike is still there. Jason then bursts through the window and throws her to her death, crashing onto the car. While a stoned Ted watches stag films with a film projector, he gets too close to the projector screen and is stabbed in the head with a kitchen knife from the other side. Jason then goes upstairs, where Doug and Sara finish making love in the shower. After Sara leaves, Jason kills Doug by crushing his head against the shower tile. When Sara screams upon finding Doug's body, she tries to escape but gets a double-bit axe through her chest.

Trish, Rob, and Gordon go next door to investigate and discover the teens' bodies. Gordon flees, and Jason kills Rob in the basement as Trish runs home, taking Rob's machete. She and Tommy barricade the house, but Jason breaks in and chases them into Tommy's room. Trish lures Jason out of the house, escapes, then returns home and is devastated to learn that Tommy did not run away. She senses Jason behind her and tries to fight him off with the machete but is overpowered. Having disguised himself to look like Jason as a child, Tommy distracts him long enough for Trish to hit him with the machete, but she merely whacks off his mask. As Trish stands horrified at Jason's deformed face, Tommy takes the machete and strikes it in the side of his skull, causing him to collapse to the floor and split his head upon impact. When Tommy notices that Jason's fingers are slightly moving, he continues to hack at his body, yelling, "Die! Die! Die!" while Trish repeatedly yells out his name.