Northern Ireland is divided into 18 parliamentary constituencies: 4 borough constituencies in Belfast and 14 county constituencies elsewhere. Section 33 of the Northern Ireland Act 1998 provides that the constituencies for the Northern Ireland Assembly are the same as the constituencies that are used for the United Kingdom Parliament.^[1] Parliamentary constituencies are not used for local government, which is instead carried out by 11 district councils; these often have different boundaries.

Each constituency returns one Member of Parliament (MP) to the House of Commons at Westminster and five Members of the Legislative Assembly (MLAs) to the devolved Northern Ireland Assembly at Stormont. Six MLAs were returned per constituency until the Assembly Members (Reduction of Numbers) Act (Northern Ireland) 2016 reduced the number to five, effective from the 2017 Assembly election.^[2]

  Democratic Unionist   Sinn Féin   Social Democratic and Labour   Ulster Unionist   Alliance Party

Data from the BBC Election Website. For full official results see the Electoral Office of Northern Ireland.

Where a cell is marked → (with a different colour of frame to the preceding cell) it indicates that the previous MP continued to sit under a new party affiliation. Changes are dated in the header row: either a general election (four-figure year, bold, link) or by-election or change in affiliation (two-figure year, italic, link or details appear on hover).

See 2023 Periodic Review of Westminster constituencies for further details.

Following the abandonment of the Sixth Periodic Review (the 2018 review), the Boundary Commission for Northern Ireland formally launched the 2023 Review on 5 January 2021. In accordance with the provisions of the Parliamentary Constituencies Act 2020, the number of constituencies allocated to Northern Ireland was unchanged, at 18.^[7] Initial proposals were published on 20 October 2021 and, following two periods of public consultation, revised proposals were published on 17 November 2022. Final recommendations were published on 28 June 2023.^[8]

Under the recommendations, the following constituencies for Northern Ireland would come into effect at the next general election:^[9]

• Politics of Northern Ireland

• List of changes to constituency boundaries: section 6 of Parliamentary constituency boundaries: the Fifth Periodical Review House of Commons Library