Lauren Ambrose (born February 20, 1978) is an American actress.

Ambrose gained recognition and critical acclaim for her starring role as Claire Fisher in the HBO drama series Six Feet Under (2001–2005), for which she was nominated for two Primetime Emmy Awards and won two Screen Actors Guild Awards. She went on to star as Jilly Kitzinger in the BBC One science fiction series Torchwood: Miracle Day (2011), Dorothy Turner in the Apple TV+ psychological horror series Servant (2019–2023), and as the adult version of Vanessa "Van" Palmer in the Showtime drama thriller series Yellowjackets (2023–present).

Her film credits include In & Out (1997), Can't Hardly Wait (1998), Psycho Beach Party (2000), Where the Wild Things Are (2009), and The Other Woman (2009). Ambrose played the title role in Loving Leah, a 2009 Hallmark film. Other credits include About Sunny (2011), Sleepwalk with Me (2012), and Wanderlust (2012).

Ambrose's stage credits include Buried Child (2004), Awake and Sing! (2006), and Exit the King (2009). She portrayed the lead role of Eliza Doolittle in the 2018 Lincoln Center Theater revival of My Fair Lady on Broadway, for which she garnered a Tony Award nomination and a Grammy Award, as well as an Outer Critics Circle Award. She is lead singer of the ragtime band Lauren Ambrose and the Leisure Class.