Ready or Not is a 2019 American horror comedy film directed by Matt Bettinelli-Olpin and Tyler Gillett, and written by Guy Busick and R. Christopher Murphy. It stars Samara Weaving, Adam Brody, Mark O'Brien, Elyse Levesque, Nicky Guadagni, Henry Czerny and Andie MacDowell. It follows a young bride who is hunted by her spouse's wealthy family as part of a wedding night ritual to worship the Devil.

Preparations began in November 2017 when Bettinelli-Olpin and Gillett, members of the filmmaking collective Radio Silence, were hired as directors, with Busick and Murphy attached to write the screenplay. After setting an initial release date, casting occurred from August to October 2018. Principal photography began later that month and concluded in November, in locations in and around Toronto, Canada and the surrounding Ontario area. Brian Tyler was hired to compose and conduct the film's score, marking his first collaboration with Bettinelli-Olpin and Gillett.

Ready or Not premiered at the Fantasia International Film Festival on July 27, 2019, and was theatrically released in the United States on August 21, 2019, by Searchlight Pictures. It received positive reviews from critics and grossed $57.6 million worldwide against a $6 million budget. It was nominated for Best Horror Film at the 46th Saturn Awards. A sequel is in development.