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