Potential enlargement of the European Union

  Current members
  Candidate states
  Potential candidates

There are five recognised candidates for membership of the European Union: Turkey (applied in 1987), North Macedonia (applied in 2004), Montenegro (applied in 2008), Albania (applied in 2009) and Serbia (applied in 2009). All have started accession negotiations.[1] Kosovo (whose independence is not recognised by five EU member states) and Bosnia and Herzegovina are recognised as potential candidates for membership by the EU. Bosnia and Herzegovina has formally submitted an application for membership, while Kosovo has a Stabilisation and Association Agreement (SAA) with the EU, which generally precedes the lodging of a membership application. Montenegro and Serbia, the most advanced candidates, are both expected to join earlier than the rest.[2] While the others are progressing, Turkish (and to a lesser extent North Macedonian) talks are at an effective standstill.[3]

The accession criteria are included in the Copenhagen criteria, agreed in 1993, and the Treaty of Maastricht (Article 49). Article 49 of the Maastricht Treaty (as amended) says that any "European state" that respects the "principles of liberty, democracy, respect for human rights and fundamental freedoms, and the rule of law", may apply to join the EU. Whether a country is European or not is subject to political assessment by the EU institutions.[4] Past enlargement since the foundation of the European Union (EU) as the European Economic Community by the Inner Six states in 1958[5] brought total membership of the EU to twenty-eight, although as a result of the withdrawal of the United Kingdom, the current number of EU member states is twenty-seven.

Of the four major western European countries that are not EU members, Norway and Switzerland have submitted membership applications in the past but subsequently frozen them, so has Iceland but subsequently withdrawn its application, while the United Kingdom is a former member. Norway, Switzerland, Iceland, as well as Liechtenstein participate in the EU Single Market and also in the Schengen Area, which makes them closely aligned with the EU; none, however, are in the EU Customs Union. In 2014, the EU signed Association Agreements with Georgia, Moldova and Ukraine.[6] The European Parliament passed a resolution recognising the "European perspective" of all three countries.[7]