William Loeb III (December 26, 1905 – September 14, 1981) was publisher of the Manchester Union Leader newspaper (later The New Hampshire Union Leader) in Manchester, New Hampshire, for thirty-five years from 1946 until his death. His unyieldingly conservative political views helped to make The Union Leader one of the best-known small papers in the country. The publication benefited from nationwide attention every four years during the New Hampshire primary.