Insidious: The Last Key is an upcoming American supernatural horror film directed by Adam Robitel and written by Leigh Whannell. It is the fourth installment in the Insidious franchise, and the second in terms of the series' in-story chronology, following 2015's Insidious: Chapter 3. The film stars Lin Shaye, Angus Sampson, Leigh Whannell, Josh Stewart, and Caitlin Gerard.

After the events in the previous film, Elise Rainier goes on to investigate the recent supernatural disturbances occurring in a family’s home in New Mexico, a house in which she used to live in her youth, diving her deeper into The Further.