Colonel Henry John Clements (16 July 1781 – 12 January 1843) was an Irish Conservative politician. He was born at Ashfield Lodge in County Cavan, the eldest son of the Rt Hon Henry Theophilus Clements and Catharine Beresford, daughter of John Beresford. He was appointed High Sheriff of Leitrim for 1804–05 and Sheriff of Cavan for 1814–15. He became a Member of Parliament for County Leitrim 1805–1818, and County Cavan 1840–1843. He also held the rank of Colonel in the Leitrim militia from 1807 to death.