Francis Stuart Chapin (3 February 1888 – 7 July 1974) was an American sociologist and educator.
He received his bachelor's degree from Columbia University in 1909, as well as his PhD from the same school in 1911. He taught economics at Wellesley College for one year. He then moved to Smith College where he taught sociology and served as department chair (1912-1921).
He played an important role in creation of a quantitative, statistical sociology in the United States in the years between World War I and World War II (1920-40).
He also served as the 25th President of the American Sociological Association. He was a prime mover in the creation of the Social Science Research Council.