William Trench

William Trench may refer to:


 * William Trench, 1st Earl of Clancarty (1741–1805), Anglo-Irish aristocrat and politician
 * William Trench, 3rd Earl of Clancarty (1803–1872), Irish nobleman
 * William Trench III (1831–1896), reeve of Richmond Hill, Ontario
 * William Le Poer Trench (1837–1920), Anglo-Irish politician and British army officer