Kim Darby (born Deborah Zerby; July 8, 1947) is an American actress and teacher. Her breakout role was as Mattie Ross in the 1969 Western film True Grit, earning her a BAFTA Award nomination for Most Promising Newcomer to Leading Film Roles. The same year, she was nominated for a Golden Globe Award for Best Actress in a Motion Picture – Musical or Comedy for her performance in counterculture comedy Generation (1969).

Darby has appeared in over 80 films and television series. She was nominated for a Primetime Emmy Award for her role in the miniseries Rich Man, Poor Man. Between 1992 and 2009, she taught acting in the extension program at the University of California, Los Angeles.