The European Union is a major reform-driving factor for accession countries. It sets standards and establishes a model for development that the countries in the region aspiring to membership should follow. The EU approach in the Western Balkans has two dimensions: (i) the EU has affected the developmental path of these countries through its role as ‘an active player’ in the mediation and conflict resolution needs of the region; (ii) the EU also acts ‘as a framework’ providing the possibility of participation in decision making for these countries and equipping them with models of governance and policy options (Noutcheva et al, 2004). In this Europeanization process, conditionality encompasses a political/democratic and economic requirement and the adoption and implementation of the EU acquis. This paper assesses the impact of the Lisbon Treaty on future accessions to the European Union.