Jennifer Jason Leigh (born Jennifer Leigh Morrow; February 5, 1962) is an American actress. She began her career on television during the 1970s before making her film breakthrough in the teen film Fast Times at Ridgemont High (1982). She received critical praise for her performances in Last Exit to Brooklyn (1989), Miami Blues (1990), Backdraft (1991), Single White Female (1992), and The Hudsucker Proxy (1994). She was nominated for a Golden Globe for her portrayal of Dorothy Parker in Mrs Parker and the Vicious Circle (1994).

Leigh starred in a 1995 film written by her mother, screenwriter Barbara Turner, titled Georgia. She co-wrote and co-directed a film with Alan Cumming titled The Anniversary Party (2001). Leigh starred in the crime drama Road to Perdition (2002) and the family drama Margot at the Wedding (2007). She had a recurring role on the Showtime comedy-drama series Weeds (2009–2012). She received critical acclaim for her voice work in Charlie Kaufman's Anomalisa (2015). For her role as fugitive Daisy Domergue in The Hateful Eight (2015), she was nominated for the Golden Globe and Academy Award for Best Supporting Actress. From 2017 to 2021, she starred in the Netflix comedy-drama series Atypical while featuring in the science fiction films Annihilation (2018) and Possessor (2020). She has since starred in the fifth season of the crime drama series Fargo (2023).

For her stage work, Leigh was nominated for a Drama Desk award for her off-Broadway performance as Beverly Moss in Mike Leigh's Abigail's Party. Her Broadway debut occurred in 1998 when she became the replacement for the role of Sally Bowles in the musical Cabaret.