EU enlargement is a key driver of long-term security, peace, stability and prosperity in Europe. It promotes common values, including democracy, the rule of law and respect of fundamental rights, while fostering economic growth.
Enlargement policy applies to countries currently aspiring to join the EU and potential candidates. The prospect of membership is a powerful stimulus for democratic and economic reforms in countries that want to become EU Member States.
The Commission helps countries wishing to join the European Union to meet the necessary criteria and supports them in implementing the related economic and democratic reforms.
The main objectives of the EU’s enlargement policy are to
- foster peace and stability in regions close to the EU's borders
- help improve the quality of people’s lives through integration and cooperation across borders
- increase prosperity and opportunities for European businesses and citizens
- guide, support and monitor changes in countries wishing to join the European Union in line with EU values, laws and standards
Seven enlargement rounds have taken place, each time transforming both the European Union and the countries that join. Today there are 27 countries in the European Union. Ten aspiring members are currently involved in the accession process.
How EU enlargement works
Which countries can join the EU?
Any European country can apply for membership if it respects the EU's democratic values and is committed to promoting them.
A country can only join if it meets all the membership criteria.
What are the steps towards joining?
There are 3 main stages that are subject to approval by all EU Member States.
During the accession process, the Commission helps countries wishing to join the EU to meet the necessary criteria for membership, and supports them in implementing the related economic and democratic reforms. The results of these reforms must be solid, sustainable and irreversible.
When the negotiations and accompanying reforms are completed and agreed by both sides, the country can join the EU – if all EU Member States agree.
Areas of action
The obligations countries must fulfil before joining the EU, and how the EU supports accession countries to establish a society based on the rule of law
How the EU supports freedom of expression and media freedom and integrity in accession countries
What the EU does to support citizen participation in social and political life in accession countries
How the EU promotes cooperation to address shared challenges in the Western Balkans region
The Western Balkans are building a common market to better integrate the region with the EU Single Market ahead of accession
The economic criteria countries must fulfil before joining the EU, and how the EU supports countries to make the necessary economic reforms
The EU provides financial and technical assistance to support reforms in the enlargement region
Key achievements
- Enlargement has increased prosperity, improved living standards, and reinforced democracy and security in both the EU and the countries involved in the accession process.
- The EU's engagement in the Western Balkans has helped to resolve conflict, promote cooperation and reconciliation, and support the region in making democratic and economic reforms.
- The EU has become the world’s largest single market which has made it an even more attractive trading partner. Since 2004 our global international trade has expanded to reach €5 trillion in 2023.
- The EU’s economy has grown by 27% since the 2004 enlargement, when 10 countries became Member States.
- Continental-scale modern infrastructure and connections have been built across the 27 Member States, thanks to EU investments and funds.
- European society has benefitted from more innovations, public and private investments, the free movement of goods, services, capital and people, higher standards and greater opportunities.
In focus
On 1 January 1986, Portugal and Spain joined the European Union, helping it grow to 12 countries and contributing to a more vibrant political, economic and cultural community. Their membership helped create millions of new jobs, modernise economies and infrastructure, and deepen trade ties. It reinforced democracy, advanced social progress, and strengthened connections between citizens through student mobility and travel. Together, the EU, Portugal, and Spain have grown stronger.
This page was last updated on 1 January 2026