Melissa Sue Anderson (born September 26, 1962) is an American-Canadian actress. She began her career as a child actress after appearing in several commercials in Los Angeles. Anderson is known for her role as Mary Ingalls in the NBC drama series Little House on the Prairie (1974–1983), for which she received a nomination for the Primetime Emmy Award for Outstanding Lead Actress in a Drama Series.

She is also known for film roles that include Vivian in Midnight Offerings (1981), Ginny in the slasher film Happy Birthday to Me (1981), and Alex in the ABC Afterschool Special, Which Mother Is Mine? (1979).Anderson became a naturalized citizen of Canada in 2007. In 2010, she published The Way I See It: A Look Back at My Life on Little House, an autobiographical account of her years acting in Little House on the Prairie.