Until recently, the term cosmopolitism could rarely be found in modern political science literature. It was only in the 1990s that the term was rediscovered by political scientists in the critical discourse on globalization. In this article, I will explore the full potential of cosmopolitism as an analytical concept for empirical political science. I will argue that the concept of cosmopolitism should not be restricted to the analysis of global politics. Indeed, cosmopolitism has much more to offer for political scientists. Properly understood, it enables – and necessitates – a re-invention of political science in the age of globalization, comparable to the behavioural revolution in political science in the 1950s. Such a paradigmatic shift should be based on a twofold transformation of existing disciplinary boundaries: A removal of the boundary between national (and comparative) and international politics on the one hand; and a re-definition of the boundaries between empirical and normative approaches on the other. As a result, cosmopolitism may serve as a new, critical theory of politics based on the integration of hitherto separated fields and sub-fields.