 William O'Brien, 2nd Earl of Inchiquin

Col. William O'Brien, 2nd Baron O'Brien of Burren, 7th Baron & 2nd Earl of Inchiquin (c.1640 – 16 January 1692) was an Irish nobleman.William O'Brien was the son of Murrough O'Brien, 1st Earl of Inchiquin and Elisabeth St. Leger, daughter of Sir William St. Leger and his first wife Gertrude de Vries of Dordrecht.