This paper focuses on the place and potential of European Security and Defence Policy ESDP in the European security structure and analyses the perception and reaction of Turkey towards such an emergent European security establishment as an example of a third country’s perception of ESDP. The paper firstly explains the development of ESDP, its content and its relationship with NATO, and discusses its place in the European security architecture. Secondly, the paper summarises the reactions of the US, Russia and other non-EU European NATO members towards the ESDP. Thirdly, the paper focuses on Turkey’s reaction towards the ESDP and analyses the reasons for its veto in NATO against the automatic recourse by the EU to NATO assets, coupled with the perception of the disruption of the balance between Greece and Turkey in the European security architecture. Finally, the paper presents an analysis of the developments that have led to the lifting of the Turkish veto and the agreement reached between the EU and NATO. It concludes that the transformation of the EU into a security actor distinct from NATO has the potential to create new dividing lines in Europe and thus the EU should preserve its civilian power image in order to continue to promote cooperation and inclusion in Europe