Elections in Northern Ireland are held on a regular basis to local councils, the Northern Ireland Assembly and to the Parliament of the United Kingdom. The Northern Ireland Assembly has 90 members, elected in 18 five-member constituencies by the single transferable vote (STV) method. Northern Ireland is represented at Westminster by 18 single-member constituencies elected by the first-past-the-post method. Unlike in the rest of the United Kingdom, elections in Northern Ireland are administered centrally by the Chief Electoral Officer for Northern Ireland and the Electoral Office for Northern Ireland rather than by local authorities.

Elections to the United Kingdom House of Commons

By-elections

Gains are marked with a grey background.

Recall petition

Referendums

Northern Ireland-specific referendums

United Kingdom-wide referendums

Elections to the Northern Ireland Assembly

Elections to the European Parliament

From 1979 to 2020, three of the seats in the European Parliament allocated to the United Kingdom formed a three-seat constituency elected by single transferable vote. It differed from European Parliament constituencies elsewhere in the United Kingdom which used the D'Hondt method. The United Kingdom withdrew from the European Union on 31 January 2020, and the constituency was abolished.

Ad hoc elections

Elections to the Northern Ireland House of Commons

By-elections

Local elections