This article summarizes the most important strands of political science interpretations of the multiple crises that are haunting the EU since 2008. The special focus is, however, on the financial and fiscal crisis. It does so first by discussing the problem of crisis definitions promoted by political and economic actors, second by outlining how (controversial) definitions came about in the EU and third by describing the resolution mechanisms that prevailing definitions entailed. It argues in more abstract terms that crises, however “wicked”, not only open windows of opportunities for more integration but also for differentiation if not for disintegration.