The European Union citizenship is a legal status 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.

EU citizens have freedom of movement, and the freedom of settlement and employment across the EU. They are free to trade and transport goods, services and capital through EU state borders, with no restrictions on capital movements or fees. EU citizens have the right to vote and run as a candidate in certain (often local) elections in the member state where they live that is not their state of origin, while also voting for EU elections and participating in a European Citizens' Initiative (ECI).

Citizenship of the EU confers the right to consular protection by embassies of other EU member states when an individual's country of citizenship is not represented by an embassy or consulate in the foreign country in which they require protection or other types of assistance. EU citizens have the right to address the European Parliament, the European Ombudsman and EU agencies directly, in any of the EU Treaty languages, provided the issue raised is within that institution's competence.

EU citizens have the legal protections of EU law, including the Charter of Fundamental Rights of the EU and acts and directives regarding protection of personal data, rights of victims of crime, preventing and combating trafficking in human beings, equal pay, as well as protection from discrimination in employment on grounds of religion or belief, sexual orientation and age. The office of the European Ombudsman can be directly approached by EU citizens.

The modern EU citizenship status partially relies on the millennia of European history and Europe's common cultural heritage. "The introduction of a European form of citizenship with precisely defined rights and duties was considered as long ago as the 1960s", but the roots of "the key rights of EU citizenship—primarily the right to live and the right to work anywhere within the territory of the Member States—can be traced back to the free movement provisions contained in the Treaty of Paris establishing the European Coal and Steel Community, which entered into force in 1952." The Treaty of Paris introduced freedom of movement for the professionals in the coal and steel industry which may be considered the nascent form of free movement that developed into EU citizenship four decades later. The citizenship of the European Union was first introduced by the Maastricht Treaty, and was extended by the Treaty of Amsterdam. Prior to the 1992 Maastricht Treaty, the European Communities treaties provided guarantees for the free movement of economically active People, but not, generally, for others. The 1951 Treaty of Paris establishing the European Coal and Steel Community established a right to free movement for workers in these industries and the 1957 Treaty of Rome provided for the free movement of workers and services. However, we can find traces of an emerging European personal status in the legal framework regulating the rights and obligations of foreign residents in Europe well before a formal status of European citizenship was introduced. In particular through the interplay between secondary European legislation and the case-law of the European Court of Justice. This formed an embryo of the future European Citizenship, and came to be defined by the practice of freedom of movement of workers within the newly established European Economic Community.

The rights of an "embryonic" European citizenship have been developed by the European Court of Justice well before the formal institution of European citizenship by the Maastricht Treaty. This could happen after the two landmark decisions in the cases Van Gend en Loos and Costa/ENEL, which established (a) the principle of direct effect of EEC law, and (b) the supremacy of European law over national law, including the constitutional one. In particular, the 1957 Rome Treaty provisions were interpreted by the European Court of Justice not as having a narrow economic purpose, but rather a wider social and economic one.

The rights associated with the European Personal Status were firstly recognized "to certain categories of workers, then expanded to all workers, to certain categories of non-workers (e.g. retirees, students), and finally perhaps to all citizens". In line with the model of social citizenship proposed by Thomas Humphrey Marshall, the "European Personal Status" or "Proto-European citizenship" was built by recognizing the social rights connected to freedom of movement and freedom of establishment in the first years of the EEC, when workers' rights in the host state were progressively extended to their family members even beyond the status of "worker", so as to promote the full social integration of the workers and their families in the host member state.

When Regulation 1612/68 abolished movement and residence restrictions for member state workers and their families in the entire EEC territory, thus ending the transitional period established by article 49 of the Rome Treaty, not only this created the conditions for a full exercise of free movement rights, but a number of important new rights were subsequently recognized by the ECJ, such as: the right to a minimum wage in the host state, the reduction of fares on public transport for large families, the right to a check for disabled adults, interest-free loans for the birth of children, the right to reside with a non-spousal partner, the payment of funeral expenses.