The Asia-Europe Parliamentary Partnership (ASEP) is a biennial meeting of Asian and European parliaments held on the sidelines of the intergovernmental Asia-Europe Meeting (ASEM) process. This dissertation studies the ASEP process development from its start in 1996 up to its 20th anniversary in 2016. This dissertation analyzes the parliamentary Asia-Europe dialogue by focusing on ASEP’s functions, identified as 1) ASEP as a place for parliamentary dialogue and empowerment, 2) ASEP a venue for norm diffusion, here focus is on Members of the European Parliament and their normative power efforts as well as on Japanese parliamentarians as norm promoters, and 3) ASEP’s role in enhancing ASEM’s democratization from the viewpoint of broader participation and better accountability. ASEP is part of the post–Cold War phenomenon of an increasing internationalization of parliamentary activities and one of around 100 international parliamentary institutions (IPIs) that aim to engage parliamentarians in regional, interregional, and global discourse more directly, bypassing the traditional national channels of parliamentary involvement in international affairs. This dissertation concludes that ASEP has grown over two decades, from a modest start to a steady process. However, ASEP suffers from several internal and external challenges, many of which are tied to the informal and uninstitutionalized nature of the entire Asia-Europe dialogue process. Therefore ASEP is currently strongest in providing parliamentary dialogue and empowerment to participating parliamentarians and in providing a place for norm diffusion. The third function remains the weakest.