Marcia Gay Harden (born August 14, 1959) is an American film and stage actress. She is the recipient of many accolades including an Academy Award and a Tony Award, in addition to nominations for a Critics' Choice Movie Award and three Primetime Emmy Awards.

She began her acting career appearing in television programs throughout the 1980s. In 1986, she appeared in her first film role, with her breakthrough coming in the 1990 Coen brothers-directed Miller's Crossing.

Her next notable film credits include The First Wives Club (1996), Flubber (1997), and Space Cowboys (2000). She received an Academy Award for Best Supporting Actress for her role as Lee Krasner in Pollock (2000). She had a supporting role in Mona Lisa Smile (2003). She received a second Academy Award nomination for her performance as Celeste Boyle in the drama film Mystic River (2003).

She appeared in several 2007 films, including Sean Penn's Into the Wild and Frank Darabont's The Mist, based on the novella by Stephen King. Also in 2007, she shared top billing with Kevin Bacon in Rails & Ties, the directorial debut of Alison Eastwood. Harden played a woman who has a mastectomy in Home (2008). (Her character in Rails & Ties also had a mastectomy.) One scene required her to bare her breasts, with the missing breast removed using computer-generated imagery. In Home, her co-stars include her daughter, Eulala Scheel.