Margaret Ruth "Maggie" Gyllenhaal (pron-en?d??l?nh??l; born November 16, 1977) is an American stage and screen actress. She is the daughter of director Stephen Gyllenhaal and screenwriter Naomi Foner Gyllenhaal (n�e Achs) and the older sister of actor Jake Gyllenhaal. She made her screen debut when she began to appear in her fathers films. Gyllenhaal later achieved recognition in a supporting role in the indie (independent film) cult hit (cult following) Donnie Darko (2001). She made her break-through role in the 2002 sadomasochistic comedy Secretary (Secretary (film)), for which she received critical acclaim and a Golden Globe (Golden Globe Award) nomination.

Gyllenhaal has appeared in an eclectic range of films, including the indie (Independent film) film Sherrybaby (2006), for which she was nominated for a Golden Globe, the romantic comedy Trust the Man (2006) and big-budget films such as World Trade Center (World Trade Center (film)) (2006) and The Dark Knight (The Dark Knight (film)) (2008). She next starred in the 2009 musical-drama Crazy Heart, for which she received an Academy Award for Best Supporting Actress nomination. Gyllenhaal has also appeared in theatrical plays, including Closer (Closer (play)) (2000) and television productions including Strip Search (Strip Search (film)) (2004).

Gyllenhaal has been in a relationship with actor Peter Sarsgaard since 2002. In 2006, the two became engaged and Gyllenhaal gave birth to their daughter, Ramona, on October 3, 2006. On May 2, 2009, she married Sarsgaard in Italy. She is a politically active Democrat (Democratic Party (United States)) and, like her brother and parents, supports the American Civil Liberties Union. Prior to the U.S.-led invasion of Iraq (2003 invasion of Iraq) she participated in anti-war demonstrations (Protests against the Iraq War). Gyllenhaal drew criticism in 2005 for her opinion that America was "responsible in some way" for the 9/11 attacks (September 11 attacks). She is actively involved in human rights, civil liberty, and anti-poverty campaigns.