Northern Ireland Act 1998

Disqualifications Act 2000 Northern Ireland Act 2000 Police (Northern Ireland) Act 2000 Postal Services Act 2000 Elections Act 2001 Political Parties, Elections and Referendums Act 2000 House of Commons (Removal of Clergy Disqualification) Act 2001 Justice (Northern Ireland) Act 2002 Tax Credits Act 2002 Northern Ireland Assembly Elections Act 2003 Northern Ireland Assembly (Elections and Periods of Suspension) Act 2003 Northern Ireland (Monitoring Commission etc.) Act 2003 Child Trust Funds Act 2004 Civil Contingencies Act 2004 Statute Law (Repeals) Act 2004 Constitutional Reform Act 2005 Government of Wales Act 2006 Northern Ireland (Miscellaneous Provisions) Act 2006 Northern Ireland (St Andrews Agreement) Act 2006 Justice and Security (Northern Ireland) Act 2007 Serious Crime Act 2007 Health and Social Care Act 2008 Northern Ireland Act 2009 Northern Ireland Assembly Members Act 2010 Postal Services Act 2011 Small Charitable Donations Act 2012 Antarctic Act 2013 Crime and Courts Act 2013 Justice and Security Act 2013 Mental Health (Discrimination) Act 2013 Childcare Payments Act 2014 Immigration Act 2014 Northern Ireland (Miscellaneous Provisions) Act 2014 Assembly Members (Reduction of Numbers) Act (Northern Ireland) 2016 Investigatory Powers Act 2016 Northern Ireland (Stormont Agreement and Implementation Plan) Act 2016 Public Services Ombudsman Act (Northern Ireland) 2016 Higher Education and Research Act 2017 Savings (Government Contributions) Act 2017 European Union (Withdrawal) Act 2018 European Union (Withdrawal Agreement) Act 2020 Executive Committee (Functions) Act (Northern Ireland) 2020 Parliamentary Constituencies Act 2020 United Kingdom Internal Market Act 2020 Elections Act 2022 Identity and Language (Northern Ireland) Act 2022 Northern Ireland (Ministers, Elections and Petitions of Concern) Act 2022 Northern Ireland (Interim Arrangements) Act 2023 Northern Ireland Troubles (Legacy and Reconciliation) Act 2023 Retained EU Law (Revocation and Reform) Act 2023 NOTOC

The Northern Ireland Act 1998 (c. 47) is an act of the Parliament of the United Kingdom which allowed Westminster to devolve power to Northern Ireland, after decades of direct rule. The act translated the 1998 multi-party agreement into law.

The act states that "Northern Ireland in its entirety remains part of the United Kingdom" and that this "shall not cease to be so without the consent of a majority of the people of Northern Ireland" voting in a dedicated border poll.

It renamed the New Northern Ireland Assembly, established by the Northern Ireland (Elections) Act 1998, to the Northern Ireland Assembly.

It repealed parts of the Government of Ireland Act 1920 and Northern Ireland Constitution Act 1973, and established new rules in line with the European Union and the Northern Ireland peace process, subsequent to the Belfast Agreement of 1998.

The act allows for a devolved Northern Ireland Assembly of 108 members. Membership of the assembly is subject to a pledge of office, which subjects the member to certain requirements with regard to standards and responsibilities. Northern Ireland remains a part of the United Kingdom until or unless a majority vote in a referendum determines otherwise. The Secretary of State for Northern Ireland holds the power to call for the referendum if it appears likely to them that a majority of the voters would express their desire to become part of a United Ireland. The assembly has the power of modifying any act of the British Parliament as far as it "is part of the law of Northern Ireland". They cannot deal, however, with reserved or excepted matters, which are of exclusive competence of the government of the United Kingdom, in consultation with the Republic of Ireland through the British-Irish Intergovernmental Conference. The Assembly has been suspended a number of times since 1998, and was re-established on Tuesday 8 May 2007, subsequent to the St Andrews Agreement of 2006.

Election to the assembly is by single transferable vote (STV), a form of proportional representation.