Patricia "Patty" MacLachlan (born March 3, 1938) is an American children's writer, who is best known for the 1986 Newbery Medal-winning novel Sarah, Plain and Tall which was later adapted as a TV movie starring Glenn Close and Christopher Walken.

She is a board member of the National Children's Book and Literacy Alliance, a national not-for-profit that actively advocates for literacy, literature, and libraries.