Mary Antin (June 13, 1881 – May 15, 1949) was an American author and immigration rights activist.
Born to Israel and Esther Weltman Antin, a Jewish family in Polotsk, Belarus, at that time part of Russia, she immigrated to the Boston area with her mother and siblings in 1894, moving from Chelsea to Ward 8 in Boston's South End, a notorious slum, as the venue of her father's store changed. She attended Girls' Latin School, now Boston Latin Academy, after finishing primary school. She married Amadeus William Grabau, a geologist, in 1901, and moved to New York City where she attended Teachers College of Columbia University and Barnard College. Antin is best known for her 1912 autobiography The Promised Land, which describes her public school education and assimilation into American culture, as well as life for Jews in Czarist Russia. After its publication, Antin lectured on her immigrant experience to many audiences across the country, and became a major supporter for Theodore Roosevelt and his Progressive Party.