Earl of Mount Alexander was a title in the Peerage of Ireland. It was created in 1661 for Hugh Montgomery, 3rd Viscount Montgomery. He was the grandson of Hugh Montgomery, known as one of the "founding fathers" of the Ulster Scots, who was raised to the Peerage of Ireland as Viscount Montgomery, of the Great Ardes, in 1622. The second Earl lost the Break of Dromore skirmish in 1689, but supported the winning side in the Williamite War. The fourth Earl represented Antrim Borough in the Irish House of Commons. The titles became extinct on the death of the fifth Earl in 1757.