Fear Street Part Three: 1666 is a 2021 American supernatural period horror film directed by Leigh Janiak, who co-wrote the screenplay with Phil Graziadei and Kate Trefry. Based on the book series of the same name by R. L. Stine, it is the third installment of the Fear Street trilogy after Part One: 1994 and Part Two: 1978, and stars Kiana Madeira, Ashley Zukerman, Gillian Jacobs, Olivia Scott Welch, Benjamin Flores Jr., and Darrell Britt-Gibson. The film follows the origins of Shadyside's curse in the mid-17th century and the survivors in 1994 who try to put an end to it.