This article addresses the problem of interest representation in regional organizations. Departing from a theory-guided four-dimensional typology, the study explores how the Association of Southeast Asian Nations (ASEAN) responded to normative challenges of its system of interest representation. The findings suggest that ASEAN has skilfully countered external democracy promotion and domestic pressures for democratizing regional governance through variable strategies including rejection, isomorphic adaptation and localization. The multiple strategies employed by the grouping have largely kept intact its ‘cognitive prior’ which rests on a blending of imported European and older local organicist ideas. Given the resilience of this cognitive prior, the prospects for a wholesale liberal-pluralist transformation of ASEAN’s system of interest representation appear dim.