Lost Girls is a 2020 American mystery drama film. Lost Girls was directed by Liz Garbus, from a screenplay by Michael Werwie, and based on the book Lost Girls: An Unsolved American Mystery by Robert Kolker. The film revolves around the murders of young female sex workers on the South Shore barrier islands of Long Island, committed by the Long Island serial killer, who remains unknown, but for which a suspect was charged July 14, 2023.

Lost Girls stars Amy Ryan as the real life activist Mari Gilbert, along with Thomasin McKenzie, Lola Kirke, Oona Laurence, Dean Winters, Miriam Shor, Reed Birney, Kevin Corrigan, and Gabriel Byrne. The film premiered at the Sundance Film Festival on January 28, 2020, and was later released on March 13, 2020, by Netflix.