Margalit Ruth Gyllenhaal Sarsgaard (/ˈdʒɪlənhɔːl/JIL-ən-hawl, Swedish: [ˈjʏ̂lːɛnˌhɑːl]; born November 16, 1977) is an American actress and filmmaker. She is the recipient of numerous accolades, including a Golden Globe Award, nominations for two Academy Awards, and two British Academy Film Awards.

Part of the Gyllenhaal family, she is the daughter of filmmakers Stephen Gyllenhaal and Naomi Achs, and the sister of actor Jake Gyllenhaal. She began her career as a teenager with small roles in several of her father's films. She appeared with her brother in the thriller Donnie Darko (2001). She then appeared in Adaptation, Confessions of a Dangerous Mind (both 2002), and Mona Lisa Smile (2003). Gyllenhaal received praise for her leading performances in the dramas Secretary (2002) and Sherrybaby (2006), both of which earned her  Golden Globe Award nominations. She had commercial success in the thriller World Trade Center (2006). She received wider recognition for her role as Rachel Dawes in the superhero film The Dark Knight (2008).