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.

Prime Ministers of Northern Ireland

#	Name	Took Office	Left Office	Party
1.	Sir James Craig	June 7, 1921	November 24, 1940 (death)	Unionist Party
2.	John Millar Andrews	November 25, 1940	May 1, 1943	Unionist Party
3.	Sir Basil Brooke	May 1, 1943	March 25, 1963	Unionist Party
4.	Terence O'Neill	March 25, 1963	May 1, 1969	Unionist Party
5.	James Chichester-Clark	May 1, 1969	March 23, 1971	Unionist Party
6.	Brian Faulkner	March 23, 1971	March 30, 1972	Unionist Party

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.