I Know What You Did Last Summer (franchise)

I Know What You Did Last Summer
Official franchise logo
Created by	Lois Duncan
Original work	I Know What You Did Last Summer (1973)
Owner	Sony Pictures Entertainment
Years	1997–present
Films and television
Film(s)	I Know What You Did Last Summer (1997) I Still Know What You Did Last Summer (1998) Untitled fourth film (2025)
Television series	I Know What You Did Last Summer (2021)
Direct-to-video	I'll Always Know What You Did Last Summer (2006)

I Know What You Did Last Summer is an American horror media franchise owned by Sony Pictures Entertainment, and consisting of three slasher films and one television series based on the 1973 novel by Lois Duncan. The first installment was written by Kevin Williamson, directed by Jim Gillespie, and released in 1997.

The first two installments star Jennifer Love Hewitt, Freddie Prinze Jr. and Muse Watson. Co-starring Sarah Michelle Gellar, Ryan Phillippe, in addition, the supporting cast includes: Johnny Galecki in the first film, with Brandy, Mekhi Phifer and Matthew Settle in the second film.