Captain John Allen, 4th Viscount Allen (b. bef. 1726 – 10 November 1753), was an Irish peer and politician.
He was the son of Hon. Richard A. Allen and Dorothy Green, and grandson of John Allen, 1st Viscount Allen. Allen sat as member of parliament (MP) for County Wicklow from 1742 until 1745, when he succeeded his cousin as Viscount Allen on the latter's death.
Allen never married and, on his death, his titles passed to his younger brother.