List of Northern Ireland Parliament by-elections
# List of Northern Ireland Parliament by-elections

This is a list of by-elections to the Northern Ireland House of Commons, from its creation in 1921 until its abolition in 1972.

| Date | Constituency | Incumbent | Incumbent | Winner | Winner | Cause |
| - | - | - | - | - | - | - |
| 2 May 1923 | Belfast West | William Twaddell | Ulster Unionist | Philip James Woods | Ind. Unionist | Death |
| 6 November 1925 | Belfast South | Philip James Woods | Ulster Unionist | Anthony Babington | Ulster Unionist | Declined seat in favour of Belfast West |
| 25 November 1925 | Armagh | Richard Best | Ulster Unionist | John Clarke Davison | Ulster Unionist | Appointed Lord Justice of Appeal |
| 10 November 1930 | North Tyrone | William Thomas Miller | Ulster Unionist | James Fulton Gamble | Ulster Unionist | Death |
| 4 June 1934 | Belfast Central | Joseph Devlin | Nationalist | Thomas Joseph Campbell | Nationalist | Death |
| 22 March 1935 | Queen's University of Belfast | Robert McNeill | Ind. Unionist | Arthur Brownlow Mitchell | Ulster Unionist | Resignation |
| 2 April 1937 | Belfast Ballynafeigh | Thomas Moles | Ulster Unionist | Frederick Thompson | Ulster Unionist | Death |
| 7 May 1937 | Foyle | James Joseph McCarroll | Nationalist | Patrick Maxwell | Nationalist | Death |
| 27 May 1937 | Larne | George Boyle Hanna | Ulster Unionist | Harold Claude Robinson | Ulster Unionist | Resignation |
| 29 September 1938 | Mid Armagh | John Clarke Davison | Ulster Unionist | Norman Stronge | Ulster Unionist | Resignation |
| 5 December 1938 | Queen's University of Belfast | Robert James Johnstone | Ulster Unionist | Howard Stevenson | Ulster Unionist | Death |
| 27 April 1939 | City of Londonderry | Edward Sullivan Murphy | Ulster Unionist | William Lowry | Ulster Unionist | Death |
| 10 November 1939 | Bannside | George Charles Gillespie Young | Ulster Unionist | Malcolm Patrick | Ulster Unionist | Death |
| 15 March 1941 | Central Armagh | David Shillington | Ulster Unionist | George Dougan | Ulster Unionist | Death |
| 27 March 1941 | North Down | James Craig | Ulster Unionist | Thomas Bailie | Ind. Unionist | Death |
| 2 July 1941 | Mid Tyrone | Hugh McAleer | Nationalist | Michael McGurk | Independent Nationalist | Death |
| 3 December 1941 | Belfast Willowfield | Arthur Black | Ulster Unionist | Harry Midgley | NI Labour | Resignation |
| 2 April 1942 | Belfast Falls | Richard Byrne | Nationalist | Eamon Donnelly | Independent Republican | Death |
| 19 October 1942 | Queen's University of Belfast | Arthur Brownlow Mitchell | Ulster Unionist | William Lyle | Ulster Unionist | Death |
| 2 July 1943 | Queen's University of Belfast | Robert Corkey | Ulster Unionist | John W. Renshaw | Ulster Unionist | Resignation |
| 11 August 1943 | North Tyrone | James Gamble | Ulster Unionist | Thomas Lyons | Ulster Unionist | Death |
| 26 August 1943 | Carrick | John Fawcett Gordon | Ulster Unionist | John Dermot Campbell | Ulster Unionist | Resignation |
| 13 December 1944 | Queen's University of Belfast | John MacDermott | Ulster Unionist | Herbert Quin | Ulster Unionist | Appointed High Court Judge |
| 12 April 1945 | South Tyrone | Rowley Elliott | Ulster Unionist | W. F. McCoy | Ulster Unionist | Death |
| 19 April 1945 | Carrick | John Dermot Campbell | Ulster Unionist | Lancelot Curran | Ulster Unionist | Death |
| 19 April 1945 | Larne | Harold Claude Robinson | Ulster Unionist | Walter Topping | Ulster Unionist | Death |
| 15 October 1945 | North Antrim | Robert Lynn | Ulster Unionist | William McCleery | Ulster Unionist | Death |
| 22 August 1946 | Belfast Central | Thomas Joseph Campbell | Nationalist | Frank Hanna | NI Labour | Resignation |
| 7 November 1946 | Bannside | Malcolm Patrick | Ulster Unionist | Terence O'Neill | Ulster Unionist | Death |
| 27 June 1947 | City of Londonderry | William Lowry | Ulster Unionist | James Godfrey MacManaway | Ulster Unionist | Resignation |
| 20 April 1948 | Queen's University, Belfast | Frederick McSorley | Independent | Samuel Irwin | Ulster Unionist | Death |
| 16 August 1948 | Mid Tyrone | Michael McGurk | Nationalist | Edward McCullagh | Nationalist | Death |
| 24 October 1949 | Enniskillen | Erne Ferguson | Ulster Unionist | Thomas Charles Nelson | Ulster Unionist | Resignation |
| 15 November 1949 | Queen's University, Belfast | William Lyle | Ulster Unionist | Frederick Lloyd-Dodd | Ulster Unionist | Death |
| 29 November 1949 | Belfast Duncairn | William Grant | Ulster Unionist | George Boyle Hanna | Ulster Unionist | Death |
| 20 January 1950 | Carrick | Lancelot Curran | Ulster Unionist | Alexander Hunter | Ulster Unionist | Resignation |
| 4 April 1950 | Belfast Woodvale | John William Nixon | Ind. Unionist | Robert Harcourt | Ulster Unionist | Death |
| 31 October 1950 | Belfast Bloomfield | Herbert Dixon | Ulster Unionist | Daniel Dixon | Ulster Unionist | Death |
| 6 December 1950 | South Armagh | Malachy Conlon | Nationalist | Charles McGleenan | Anti-Partition | Death |
| 2 February 1951 | Antrim | Hugh Minford | Ulster Unionist | Nat Minford | Ulster Unionist | Death |
| 18 June 1951 | City of Londonderry | James Godfrey MacManaway | Ulster Unionist | Edward Warburton Jones | Ulster Unionist | Resignation |
| 10 December 1951 | South Antrim | John Milne Barbour | Ulster Unionist | Brian McConnell | Ulster Unionist | Death |
| 8 May 1954 | Enniskillen | Thomas Charles Nelson | Ulster Unionist | Harry West | Ulster Unionist | Death |
| 15 October 1955 | Central Armagh | George Dougan | Ulster Unionist | Isaac Hawthorne | Ulster Unionist | Death |
| 15 November 1955 | Belfast Woodvale | Robert Harcourt | Ulster Unionist | Neville Martin | Ulster Unionist | Elected Lord Mayor of Belfast |
| 23 November 1956 | Belfast Windsor | Archibald Wilson | Ulster Unionist | Herbert Kirk | Ulster Unionist | Resignation |
| 4 December 1956 | Belfast Duncairn | George Boyle Hanna | Ulster Unionist | William Fitzsimmons | Ulster Unionist | Resignation |
| 5 March 1959 | West Down | John Edgar Bailey | Ulster Unionist | David John Little | Ulster Unionist | Death |
| 28 May 1959 | Belfast Clifton | Robin Kinahan | Ulster Unionist | William James Morgan | Ulster Unionist | Elected Lord Mayor of Belfast |
| 5 February 1960 | Larne | Walter Topping | Ulster Unionist | William Craig | Ulster Unionist | Resignation |
| 16 February 1960 | Belfast Shankill | Henry Holmes | Ulster Unionist | Desmond Boal | Ulster Unionist | Resignation |
| 9 July 1960 | South Londonderry | Dehra Parker | Ulster Unionist | James Chichester-Clark | Ulster Unionist | Resignation |
| 29 November 1960 | North Londonderry | Robert Moore | Ulster Unionist | Joseph Burns | Ulster Unionist | Death |
| 20 April 1961 | Belfast Bloomfield | Daniel Dixon | Ulster Unionist | Walter Scott | Ulster Unionist | Resignation |
| 22 November 1961 | Queen's University, Belfast | Samuel Irwin | Ulster Unionist | Sheelagh Murnaghan | Ulster Liberal | Death |
| 6 December 1962 | Belfast Cromac | Joseph Morgan | Ulster Unionist | William Kennedy | Ulster Unionist | Death |
| 9 May 1964 | Iveagh | Brian Maginess | Ulster Unionist | Samuel Magowan | Ulster Unionist | Appointed County Court Judge |
| 30 June 1964 | East Tyrone | Joseph Francis Stewart | Nationalist | Austin Currie | Nationalist | Death |
| 3 December 1964 | Mid Down | John L. O. Andrews | Ulster Unionist | Basil Kelly | Ulster Unionist | Elected to Senate |
| 19 June 1965 | West Down | David John Little | Ulster Unionist | John Dobson | Ulster Unionist | Appointed Recorder of Londonderry |
| 23 November 1966 | Queen's University, Belfast | Charles Stewart | Independent | Robert Porter | Ulster Unionist | Resignation |
| 25 May 1967 | South Down | Joseph Connellan | Nationalist | Michael Keogh | Nationalist | Death |
| 22 March 1968 | Lisnaskea | Basil Brooke | Ulster Unionist | John Brooke | Ulster Unionist | Resignation |
| 16 May 1968 | City of Londonderry | Edward Warburton Jones | Ulster Unionist | Albert Anderson | Ulster Unionist | Appointed High Court Judge |
| 6 November 1968 | South Antrim | Brian McConnell | Ulster Unionist | Richard Ferguson | Ulster Unionist | Resignation |
| 16 April 1970 | Bannside | Terence O'Neill | Ulster Unionist | Ian Paisley | Protestant Unionist | Resignation |
| 16 April 1970 | South Antrim | Richard Ferguson | Ulster Unionist | William Beattie | Protestant Unionist | Resignation |
| 12 November 1970 | Belfast St Anne's | Norman Laird | Ulster Unionist | John Laird | Ulster Unionist | Death |
