The goal of this Special Issue is to improve our conceptualisation and empirical understanding of EU actorness and effectiveness in International Relations. While the European Union aspires to play a greater global role, its actorness and effectiveness cannot be taken for granted given the nature of the EU as a multi-level and semi-supranational polity encompassing 28 Member States with diverse foreign policy preferences. The EU is presently at an important crossroad. On the one hand, its external policy stature and capacity have been boosted by institutional innovations and by the Union�s increased involvement in the full spectrum of international issues. On the other hand, a number of factors cast doubt on the EU�s real external policy actorness and effectiveness: slow and often only modest internal reforms, an increasing politicisation of formally �low politics� issues, the prolonged sovereign debt crisis in the Eurozone, and a less favourable external environment, with the US shifting its focus to the Asia-Pacific region and emerging powers creating a more polycentric world order. In view of these changes and subsequent developments in the scholarly literature, our aim is to re-evaluate earlier conceptions of EU actorness. Central to this re-evaluation will be a shift in focus from notions of actorness to effectiveness. This introductory article will unpack and further elaborate the issues raised in this abstract by delineating the EU as an international actor in the empirical context, by reviewing the existing conceptual literature, defining and conceptualizing key notions and by providing an overview of the contributions to this Special Issue.