Warren Otis Arnold (June 3, 1839 – April 1, 1910) was a U.S. Representative from Rhode Island. Born in Coventry, Rhode Island, Arnold attended the common schools.He engaged in mercantile pursuits at Coventry from 1857 to 1864.He was a manufacturer of cotton goods in Chepachet and Westerly, Rhode Island, until 1866 when he began the manufacture of woolen goods.