Albert Glenn Barr OBE was a politician from Derry, Northern Ireland, who was an advocate of Ulster nationalism. For a time during the 1970s he straddled both Unionism and Loyalism due to simultaneously holding important positions in the Vanguard Unionist Progressive Party and the Ulster Defence Association.

Ulster nationalism is a minor school of thought in the politics of Northern Ireland that seeks the independence of Northern Ireland from the United Kingdom without joining the Republic of Ireland, thereby becoming an independent sovereign state separate from both.