This article introduces the theme of ‘Europeanization’ in the context of the focus on contemporary southern and Mediterranean Europe. In applying the term ‘periphery’ to the region, it argues that the major contrasts that exist between it and the ‘core’ EU states serve to highlight in stark terms the challenges endemic within the Europeanization process. It explores the different meanings of ‘Europeanization’ and argues that it necessitates a broad focus and a complex ontology. The case studies that follow are placed within the perspective of domestic institutional adaptation, albeit in multi-tiered, core-periphery setting. The southern experience highlights the dynamism, asymmetry and fragmentation of the Europeanization process. These attributes are of increasing significance both to an understanding of the patterns of change underway in the region and to the future stability and cohesion of the EU itself.