William Smith (ca. 1762 – June 26, 1840) was an American politician from the state of South Carolina. He served two terms as a Senator in the United States Senate, the first from 1816 to 1823 and the second from 1826 to 1831. During his life Smith was one of the most prominent political leaders in the state of South Carolina. He formed an intense rivalry with John C. Calhoun, arguing against Calhoun's nationalist views, and advocating for states' rights.