The EU was always designed to connect more countries than the original six that founded the Union in 1957. Between 1973 and 2013, the EU saw seven enlargements, bringing the EU member states up to 28 in total:

  • 1973 – Denmark, Ireland, UK
  • 1981 – Greece
  • 1986 – Portugal, Spain
  • 1995 – Austria, Finland, Sweden
  • 2004 – Czech Republic, Cyprus, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, Slovenia
  • 2007 – Bulgaria, Romania
  • 2013 – Croatia

The Copenhagen Criteria

The Treaty on European Union states that any European country may apply to join the EU if it respects the Union’s democratic values and is committed to promoting them. More specific criteria are known as the Copenhagen Criteria. They state that a country may only join the EU if:

  • politically – it has stable institutions guaranteeing democracy, the rule of law and human rights;
  • economically – it has a functioning market economy and is able to cope with competitive pressure and market forces within the EU;
  • legally – it accepts established EU law and practice, particularly the major goals of political, economic and monetary union.

The accession process has a number of stages, all of which must be approved by all existing EU member states for a country to be accepted as a member. A country is first granted the prospect of membership. It then becomes an official candidate for membership, before finally moving on to official membership negotiations. When negotiations and accompanying reforms have been completed, the country may join the EU.


In 2012, the EU launched a new ‘positive agenda’ for EU-Turkey relations. Intended to put the accession process back on track after a period of stagnation, the initiative will promote reforms in Turkey in areas of mutual interest, and where progress is both needed and feasible.

Both Kosovo (under UNSCR 1244/99) and Serbia’s progress towards EU membership are linked to ongoing negotiations between the two, known as the ‘Pristina-Belgrade Dialogue’. The talks are mediated by the EU and address regional cooperation, freedom of movement and rule of law.

Good neighbours

Stronger relations and cooperation with countries just outside Europe are assured by the EU’s European Neighbourhood Policy. For those countries to the south and the east of the EU’s borders, the policy offers more than standard cooperation and trade agreements.

EU relations with Kosovo (under UNSCR 1244/99) 
The European Commission’s Enlargement Directorate-General