The ASEAN region, with its 10-member states, as it stood at the beginning of the 21st century, presented huge gaps between levels of development of member states. Over the last two decades one observes a relative convergence in countries' levels (even if the gap is still quite important) but an increase in inequalities within countries. Even if this dual movement can be found in many groups of trade partners, and in first instance in the EU, the replication of this dual movement may be surprising in a set of countries with such differences in development levels. The paper will try to investigate whether this dual evolution is likely to persist or recede in the medium term and to what extent a regionalisation process, mainly based on trade liberalisation, is the main factor at work. An assessment of the contribution to this dual dynamic of the various sectors, whether agriculture, raw materials or manufacturing, will be attempted as it may hint at specific trade policies to limit rises in within-country inequalities which run the risk at the end to ruin the benefits of the regionalisation process. Historical specificities of Europe and ASEAN regional integration Regional integration is supposed to foster convergence of living standards on the long run as it creates catching-up opportunities for less developed member states. Better access to an enlarged market, attraction of foreign direct investment, transfer of technologies, improved infrastructure and connectivity are the economic drivers of the process of convergence. These economic factors combine with institutional and socio-political drivers such as political agreements on common policy objectives, adoption of common regulatory framework, procedures and norms regarding production, trade, skills, migration and sometimes, education and social rights.