Mary Duncan (disambiguation)

Mary Duncan (1894–1993) was an American stage- and film actress.

Mary Duncan may also refer to:


 * Mary Duncan (writer) (born 1941), American writer, publisher, and educator
 * Mary Ellen Duncan (1941–2022), American academic administrator and teacher
 * Mary Lundie Duncan (1814–1840), Scottish poet and hymnwriter
 * Mary Duncan, co-founder of W & M Duncan and Company
 * Mary Duncan Library, Benson, North Carolina
 * Mary Duncan, fictional character in The House by the Churchyard