A member state is a state that is a member of an international organisation.

A member state of the European Union is a state that is party to treaties of the European Union (EU) and thereby subject to the privileges and obligations of EU membership. Unlike the membership of an international organisation, EU membership entails each member being placed under binding laws in exchange for representation in the EU's legislative and judicial institutions. On the other hand, EU states retain considerable autonomy compared to the constituent states of a federation (such as a U.S. state), maintaining their national military and foreign policy (where they have not agreed to European action in these areas).

Die Europäische Union (EU) besteht seit 2007 aus 27 Mitgliedstaaten (Unionsmitgliedstaaten).

Les 27 pays membres de l'Union européenne sont de tailles différentes et présentent des modes d'organisation institutionnelle variés. Ensemble, ils forment l'Union européenne, un espace de près de 500 millions d'habitants et de km².

Страны-члены Евросоюза на 1 января 2007:

Особые территории вне Европы, также входящие в Европейский Союз:

• Список стран ЕС, сортировка по численности населения