Northern Ireland ( ; Ulster-Scots: ') was a constituency of the European Parliament from 1979 until the UK exit from the European Union on 31 January 2020. It elected three MEPs using the single transferable vote, making it the only constituency in the United Kingdom which did not use first-past-the-post or party-list proportional representation.
The constituency covered the entirety of Northern Ireland, a constituent country of the United Kingdom. It was the only constituency in the United Kingdom the boundaries of which remained unchanged from the first direct election in 1979 until the UK left the European Union in 2020.