The Association of South-East Asian Nations (ASEAN) represents the world’s second most influential regional integration project after the European Union (EU). Its fiftieth anniversary in August 2017 prompted extensive commentary on the achievements of this important regional grouping as well as on the challenges and opportunities that it confronts as it begins its second half-century. This article draws on those commentaries to present a stock-take of ASEAN at fifty from a liberal perspective. While acknowledging ASEAN’s achievements over the last fifty years, it highlights the daunting challenges that threaten the grouping’s efficacy and cohesion, with attendant implications for wider regional architecture in the Asia-Pacific region. From rising nationalism to the constraints of the ‘ASEAN Way’ and the slow progress of the ASEAN Economic Community, the ‘centrality’ of the organisation for its member states is in question. External pressures posed by turbulent geopolitical tides make ASEAN’s hard-won ‘centrality’ in wider Asia-Pacific affairs an even more contested concept. There are nonetheless opportunities for ASEAN to avert a mid-life crisis and revitalise regional integration. ASEAN’s best chance of doing so is to apply liberal approaches to regional order in ways that will strengthen rules-based institutions, collective security, political dialogue, economic openness and tolerance of differences.