Alexander Robert Stewart (12 September 1795 – 25 March 1850) was an Irish landowner and member of parliament.
He was the son of Alexander Stewart of Ards by his wife Lady Mary, daughter of Charles Moore, 1st Marquess of Drogheda.
His uncle was Robert Stewart, 1st Marquess of Londonderry and he was first cousin to Robert Stewart, Viscount Castlereagh (Secretary of State for Foreign Affairs during the Napoleonic Wars and principal British diplomat at the Congress of Vienna) and Charles Vane, 3rd Marquess of Londonderry.
[1] He was commissioned as Lieutenant-Colonel of the disembodied Londonderry Militia in October 1822 following the death of his cousin Castlereagh, who had been Colonel of the regiment.
Alexander Robert Stewart lived at the family estate of Ards House, Dunfanaghy, County Donegal.