Kim Darby is an American actress best known for her roles as Mattie Ross in True Grit (1969) and Jenny Meyer in Better Off Dead (1985).

True Grit is a 1969 American Western film directed by Henry Hathaway, starring John Wayne as U.S. Marshal Rooster Cogburn, Glen Campbell as La Boeuf and Kim Darby as Mattie Ross. It is the first film adaptation of Charles Portis' 1968 novel of the same name. The screenplay was written by Marguerite Roberts. Wayne won an Oscar for his performance in the film and reprised his character for the 1975 sequel Rooster Cogburn.