Ethan Allen Greenwood (1779–1856) was an American lawyer, portrait painter, and entrepreneurial museum proprietor in Boston, Massachusetts, in the early 19th century. He established the New England Museum in 1818. In 1806 he graduated from Dartmouth College. He also studied at West Point. Between 1801 and 1825, Greenwood produced many portraits, perhaps as many as 800 works. He utilized the physiognotrace technique, an early pre-photographic intaglio printing method used to mechanically transpose an image to a printing plate. He kept a studio in Boston c. 1813 and associated with other artists, including Gilbert Stuart.