Lieutenant-Colonel Thomas Howard, 3rd Earl of Effingham, PC (13 January 1746 – 19 November 1791), styled Lord Howard until 1763, was a British nobleman and Army officer, the son of Thomas Howard, 2nd Earl of Effingham, and his wife Elizabeth. Lord Howard was commissioned an ensign and lieutenant in the 2nd Regiment of Foot Guards on 20 February 1762. He was promoted to captain in the 5th Regiment of Foot on 13 September 1765. In 1770 at the age of 24, he fought as a volunteer in the Russian army during the Russo-Turkish War and was present at the destruction of the Turkish fleet at Chesma Bay.