William Hawkins Polk (May 24, 1815 – December 16, 1862) was an American politician and a member of the United States House of Representatives for Tennessee's 6th congressional district from 1851 to 1853. He was the younger brother of President James K. Polk. Prior to his election to Congress, he had been a member of the Tennessee House of Representatives (1841–1845), served as U.S. Minister to the Kingdom of the Two Sicilies (1845–1847), and fought as a major in the Mexican–American War.