The Prime Minister of Northern Ireland was the head of the Government of Northern Ireland, appointed by the Governor of Northern Ireland under the Government of Ireland Act, 1920. The system of government created by the Act, of a bicameral legislature, with a majoritarian system of home rule, was abolished in 1972.

The Prime Ministers of Northern Ireland were:

  • Sir James Craig Bt. (1921-40) [later created Viscount Craigavon]
  • John Millar Andrews (1940-43)
  • Sir Basil Brooke (1943-63) [later created Lord Brookeborough]
  • Terence O'Neill (1963-69) [later created Lord O'Neill of the Maine]
  • James Chichester Clarke (1969-71) [later created Lord Moyola]
  • Brian Faulkner (1971-72) [later created Lord Faulkner].

A new office, First Minister of Northern Ireland was created by the Belfast Agreement. In contrast with the majoritarianism of the earlier Stormont regime, the new power-sharing assembly operates on the principles of consociational democracy.