This study provides a systematic account of European adaptation (Europeanization) of the national core executive in Luxembourg. So far the existing literature on European adaptation processes regarding national officials and their administrative structures does not address the case of Luxembourg nor does it link the analysis of European adaptation of actors and institutions in one research design. The analytical framework used in order to unveil Europeanization processes in the case of Luxembourg encompasses a mixed-method approach using quantitative but mostly qualitative techniques. The discovery of the way Luxembourg manages the coordination of its EU policy and the extent to which the core executive has been affected by the European socialization process provides evidence of successful European adaptation of the Luxembourgish core executive to the EU. Displaying a coordination system of EU policy that is structured by informal procedures, the flexibility and pro-integrationist outlook of national civil servants is mainly responsible for Luxembourg’s efficient management of EU affairs. Despite being one of the smallest member states in the EU, Luxembourg has created a coordination system for EU policy that ensures successful management of its work in the European arena. While uncovering institutional and individual adaptation processes in Luxembourg, this thesis is the first systematic account that integrates socialization and coordination issues together into the Europeanization research agenda.