The article analyzes the evolution of Finland’s security policy in the context of its interaction with the European Union. It examines the historical foundations of Finland’s security model, including the strategy of neutrality during the Cold War. Particular attention is paid to the transformation of Finland’s foreign and security policy after its accession to the European Union in 1995 and its participation in the development of the EU’s Common Foreign and Security Policy and the European Security and Defence Policy. The study demonstrates that the development of Finland’s security policy has gone through two main stages — «Europeanisation» and «Euro-Atlantisation». At the first stage, the country sought to strengthen its security through institutional integration into EU structures and participation in EU missions. At the second stage, cooperation with NATO became increasingly important. The article concludes that while the EU played a significant role in transforming Finland’s security policy, Euro-Atlantic structures remain the key military guarantee of the country’s security.