The accession negotiations between the European Union and Turkey are the most complicated in the EU's enlargement history. After Turkey's refusal to expand the Customs Union on Cyprus, the European Council decided towards the end of 2006 to freeze 8 of 35 chapters in the entry process. Although both sides underline their interest in Turkish accession, they discuss integration options beyond full membership. Within this debate, the main question is the following-. Should the EU-Turkey cooperation be extended along deepening intergovernmental cooperation or along integrating Turkey into the supranational EU structures? The model of Gradual Integration enriches this debate and could develop into a realistic option for integration for the EU and Turkey. It is based on the Customs Union which has existed between both sides since 1996 and foresees a thematic and temporarily dynamic intergovernmental integration in three phases. This could be developed along the concepts "Core Europe" and "Europe of Variable Geometries". The novelty is ~ in contrast to other integration models - that Gradual Integration foresees for Turkey the right to participate in decision-making. Furthermore, the possibility of Turkish full membership could be foreseen after the implementation of the last integration phase.