The third and final entry in the original Poltergeist film series, it follows young Carol Anne Freeling, who is terrorized by malicious spirits while staying in her aunt and uncle's apartment at Chicago's John Hancock Center.

The Freeling family has sent Carol Anne away from her native California to live with Diane's wealthy sister Pat and her husband Bruce Gardner in Chicago.

Pat and Bruce are unaware of the events that the Freeling family had endured in the previous two films, only noting that Steven was involved in a bad land deal.

Writer-director Gary Sherman drafted the original screenplay of Poltergeist III with screenwriter Brian Taggert, whom he had worked with on Wanted: Dead or Alive (1987).

[4] Additionally, Sherman was influenced by Lewis Carroll's Alice novel Through the Looking-Glass, which served as a framework for the film's narrative, specifically the use of mirrors as a plot device.

[5] Heather O'Rourke and Zelda Rubinstein reprised their roles from the previous two films (as Carol Anne Freeling and Tangina Barrons, respectively) the only cast members to do so.

[1] According to actress Nancy Allen, one of the earliest scenes she filmed was the finale sequence in which she and Skerritt's characters attempt to scale the building on a window cleaning platform.

[5] Because of recurrent budgetary restrictions that arose during the shoot, director Sherman was forced to make unexpected alterations to his and Taggert's original screenplay.

On May 13, 1987, while filming the snow-covered parking garage sequence in Oakbrook Terrace's Mid America Plaza, a special effects explosion caused six polystyrene foam-covered cars to catch fire.

[1] At the time Poltergeist III began shooting in spring of 1987, Heather O'Rourke had been ill with flu-like symptoms and subsequently underwent medical treatment during parts of the filming.

In late January 1988, O'Rourke suddenly became ill again, her condition rapidly deteriorated, and she died on February 1, 1988 (barely a month after her 12th birthday) during Poltergeist III's post-production period.

[9][10] After the completed film was rated PG by the MPAA in November 1987, Sherman and the studio decided to re-shoot at least part of the ending with a different special effects sequence.

In the original ending that was scrapped after O'Rourke's death, when Patricia jumps through the glass pane into the apartment, she finds Carol Anne, Donna, Scott, Bruce and Tangina frozen and dying.

Planning and design for the new SFX make-ups took place between December 1987 and January 1988, with a possible shooting date set for early February.

Ebert said that when he went to see the film, the audience in the theater also became annoyed at the tactic and started screaming back the names towards the screen.

[16] Janet Maslin of The New York Times wrote that "Gary Sherman, who directed and co-wrote the film, has no notion of creating a coherent universe through the looking glass.

"[17] Variety stated, "Following the pattern set by his 'Poltergeist' predecessors, director-co-writer Gary Sherman demonstrates absolutely no interest in whether this film ever has a modicum of meaning as he rushes from one special effect to another.

"[18] Michael Wilmington of the Los Angeles Times called it "another sequel that seems to exist for no better reason than justifying its title and number ...

The acting plummets into realms of posturing camp, howling corn and eye-rolling hamminess that shatter illusion like a dropped glass.

quality of the special effects, but went on to write, "Sherman gives it a shot, but he can't quite get the family tensions going that provided a psychological undercurrent for the supernatural events in Parts 1 and 2.

"[20] Hal Hinson of The Washington Post wrote, "Gary Sherman, the film's co-writer and director, has set up a showcase for scary effects, and some of them are rather nice, in a grisly sort of way.

On January 31, 2017, Scream Factory released a Blu-ray Collector's Edition of the film including new commentaries and featurettes and the original ending before it was reshot.