Charles Sydney Hopkinson (July 27, 1869 – October 16, 1962) was an American portrait painter and landscape watercolorist. He maintained a studio in the Fenway Studios building in Boston from 1906 to 1962. He painted beyond 800 portraits in a forward style considering a palette gradually lightening through his career. Many of his paintings were commissioned by U. S. East Coast institutions, especially Harvard University, where he acted as house portraitist. Among his sitters were Oliver Wendell Holmes, Calvin Coolidge, Lewis Perry and John Masefield.