Mary Megan "Mare" Winningham (born May 16, 1959) is an American actress and singer-songwriter.

Her Disney roles include Ginny in Tru Confessions, Prudence Crandall in the 1991 television movie, She Stood Alone, Dr. Emily Carson in Turner & Hooch, Larissa Johnson in the 2008 Touchstone Pictures film, Swing Vote, Nancy Riverton in the CBS/ABC TV show, Criminal Minds, and Susan Grey in six episodes of Grey's Anatomy.