This paper examines the relationship between Europeanisation and the recent changes of the Norwegian and Swedish security identities. Since the mid-1990s, these two countries have gone different ways, the former as an active non-member with no decision-making powers and the latter as an active participant in the development of the European Security and Defence Policy (ESDP). Concerning Norway and Sweden’s security identity, both have changed exceedingly over the years. Norway, which has valued the US and the transatlantic partnership through NATO, namely being an ‘Atlanticist’, seeks a deeper connection to the EU as a security actor over the last fifteen years, despite the authorities emphasizing that NATO remains the cornerstone for Norwegian security policy. Sweden, which maintained strongly neutral and non-aligned throughout the 20th century, was initially sceptic to partaking in the security and defence dimension of the Union. Nonetheless, Sweden, as a member, managed to change its perception of EU’s security policy through highlighting crisis management and turned out to become one of EU’s most active contributors in shaping the ESDP. This paper concludes that Norway and Sweden have seen similar outcomes concerning Europeanisation, despite holding different positions in relation to the EU. Norway has not been able to hold an influential role respecting its European integration process, even though the authorities seek to gain as much input as possible into the ESDP through associate membership. Sweden, in contrast, entered the Union with an initial negative attitude concerning the security and defence policy but has changed its perception and chosen to play an active part in the policy making process through influencing and deepening its cooperation.