Thora Birch (born March 11, 1982) is an American actress. She made her film debut in Purple People Eater (1988), for which she won a Young Artist Award for Best Young Actress Under Nine Years of Age, and rose to early prominence as a child star with her performances in films such as All I Want for Christmas (1991), Patriot Games (1992), Hocus Pocus (1993), Monkey Trouble (1994), Now and Then (1995) and Alaska (1996).

Her breakthrough role came in 1999 with the highly acclaimed film American Beauty, which brought Birch to international recognition, earning her a nomination for the BAFTA Award for Best Actress in a Supporting Role. She then played the lead role in Ghost World (2001), for which she was nominated for the Golden Globe Award for Best Actress – Motion Picture Musical or Comedy. In 2003, Birch starred in Homeless to Harvard: The Liz Murray Story, which earned her a nomination for the Primetime Emmy Award for Outstanding Lead Actress in a Miniseries or Movie. Birch has since appeared in independent films, including Dark Corners (2006), Winter of Frozen Dreams (2009) and Petunia (2012).

After taking a break from acting, she resumed her career in 2016 and starred as Morgan in the first season of the sci-fi television series Colony, as well as starring in four independent films, and the Plan B and A24 film The Last Black Man in San Francisco.