This paper attempts to apply the three so called new institutionalist schools on European transnational party organizations (Europarties); rational choice institutionalism, sociological institutionalism and historical institutionalism. Two questions are guiding the discussion. The first is whether institutionalist approaches can deepen our understanding of Europarties. The second question is which one of the three schools of new institutionalism can best contribute to the discussion of Europarties. The paper departs from how each institutionalist school has been applied to the analysis of the EU and endeavors thereafter to apply those experiences on the Europarties. The conclusion is that institutionalist perspectives can indeed enrich our understanding of Europarties. When it comes to which one of the schools that is most appropriate, the conclusion is that they each contribute in their own way.