Ready or Not is a 2019 American black comedy horror 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, 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.

Mark O'Brien is a Canadian actor and director best known for his roles as Des Courtney in Republic of Doyle and Tom Rendon in Halt and Catch Fire. He won the Canadian Screen Award for Best Actor at the 8th Canadian Screen Awards for his performance as Terry Sawchuk in the biographical drama film Goalie.