The primary law governing nationality of Ireland is the Irish Nationality and Citizenship Act, 1956, which came into force on 17 July 1956. Ireland is a member state of the European Union (EU) and all Irish nationals are EU citizens. They are entitled to free movement rights in EU and European Free Trade Association (EFTA) countries and may vote in elections to the European Parliament.

European Union citizenship is afforded to all nationals of member states of the European Union (EU). It was formally created with the adoption of the 1992 Maastricht Treaty, at the same time as the creation of the EU. EU citizenship is additional to, as it does not replace, national citizenship. It affords EU citizens with rights, freedoms and legal protections available under EU law.