Marcia Gay Harden (born August 14, 1959) is an Oscar-winning American actress.

Harden was born in La Jolla, California, as one of five children. Her father, Thaddeus Harden, was in the Navy. She graduated from Surrattsville High School in Clinton, Maryland in 1976. Harden graduated from the University of Texas at Austin with a B.A. in theatre and earned an MFA from the graduate theatre program of New York University.

Harden debuted on Broadway in Tony Kushner's Angels in America in 1993. For her film work, she won a Best Supporting Actress Academy Award for Pollock (2000), and was nominated in the same category for Mystic River (2003).

Other notable films include The Imagemaker (1986), her first screen role, in which she played a stage manager; the Coen Brothers' Miller's Crossing (1990), a 1930s mobster drama in which she gained her first wide exposure; the Disney sci-fi comedy Flubber (1997), a popular hit in which she co-starred with Robin Williams; the supernatural drama Meet Joe Black (1998); Labor of Love (1998), a Lifetime Television movie in which she starred with David Marshall Grant; and an all-star adventure-drama of aging astronauts, Space Cowboys (2000).

Her niece, Audrey Harden (1993-December 16, 2003), died in Astoria, New York of burns from a house fire, along with her nephew and ex-sister-in-law.

Harden is married to Thaddaeus Scheel, with whom she worked on The Spitfire Grill (1996), and the couple have three children: a daughter, Eulala Grace Scheel, and twins Julitta Dee Scheel and Hudson Harden Scheel.