The European Neighbourhood Policy (ENP) has frequently been described as successor to the European Union’s (EU) enlargement policy (Comelli 2004; Dannreuther 2006), thereby placing it in a context of European expansion. Although, in contrast to enlargement, the ENP does not aim at the advancement of the EU’s geographic borders, it is a policy promoting or even projecting European interests, norms and principles in its geographic vicinity. Hence, despite covering almost the entire neighbourhood to the East and the South of the EU and of its current (potential) candidates, the ENP does not include Western European neighbours, like Switzerland or Norway. This selective definition of ‘neighbourhood’ has long been associated with an agenda of creating a sort of buffer zone around the EU to protect it from negative outside developments. Discussing the notion of the ENP as an effort to establish a European buffer zone, the chapter will first focus on the academic debate related to the general conception of borders and boundaries underlying the ENP. It will then consider major policy documents giving guidance to the ENP to assess how far such interpretations match with the actual formulation of the ENP. The chapter concludes by displaying empirical data on major issues put forward by the EU when conceptualising the ENP in order to scrutinise in how far ENP countries can truly be considered a buffer zone from an EU point of view.