How EU enlargement works
The EU integrates new members through the enlargement process once they meet a number of political and economic conditions. Each candidate country needs to fulfil the same conditions and complete the same steps.
What is EU enlargement?
Enlargement is the process whereby states join the European Union, after they have fulfilled a set of political and economic conditions.
Any European state which respects EU democratic values and is committed to promoting them may apply for EU membership.
Accession criteria
The accession criteria, or Copenhagen criteria (named after the 1993 Copenhagen European Council meeting which defined them), are the essential conditions all candidate countries must satisfy to become an EU member state. These are:
- political criteria: stability of institutions guaranteeing democracy, the rule of law, human rights and respect for and protection of minorities
- economic criteria: a functioning market economy and the capacity to cope with competition and market forces
- administrative and institutional capacity to effectively implement the EU acquis (body of common rights) and ability to take on the obligations of EU membership
The EU's capacity to take in new members, while maintaining the momentum of European integration, is also an important consideration.
Accession steps
After a state has applied for EU membership and its request has been agreed to by all EU member states, the accession process can begin. The opening of the formal accession negotiations requires the agreement of all EU member states. These negotiations help prepare the candidate for eventual membership and focus on the adoption of the established EU law and implementation of the needed judicial, administrative and economic reforms.
When negotiations on all policy areas are completed, and the EU itself is prepared for enlargement in terms of absorption capacity, then the terms and conditions for accession — including possible safeguard clauses and transitional arrangements — are incorporated into an accession treaty. This treaty needs the European Parliament’s consent and the Council’s unanimous approval before all EU member states and the candidate country can sign it.
After all the contracting parties have ratified the accession treaty in line with their respective constitutional rules, the candidate becomes an EU member state on the date set out in the accession treaty.
Role of the Council
The Council (under the General Affairs Council configuration) supervises the EU enlargement process and the accession negotiations, which are intergovernmental by nature. On matters related to the enlargement policy, the Council generally operates by way of unanimous agreement between all the EU member states.
Every year, the Council takes stock of progress made on the enlargement process and typically approves conclusions. On 16 December 2025, the Danish Council presidency issued conclusions that were politically supported by 26 member states. These conclusions assessed the situation in each of the EU's partners and set out political priorities and guidelines for further reforms.
Last review: 4 November 2025