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.
| # | Name | Took Office | Left Office | Party |
|---|---|---|---|---|
| 1. | Sir James Craig | June 7, 1921 | November 25, 1940 | Unionist Party |
| 2. | John Miller 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 25, 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.