This paper demonstrates that multilateralism and regionalism are complementary, and that regional income convergence is likely with a like-minded and committed regionalism that often has links culturally and geographically. The association between international trade, income per capita, regional income convergence in ASEAN-5 is explored by applying the Lumsdaine and Papell approach that allows two endogenous structural breaks. The causal relationships between the above variables are also studied using Granger causality tests. The conclusion is that global (non-discriminatory multilateral) reforms have had a large impact on increasing trade. There is also a two-way causal relationship between the flow from trade to regional income convergence, and vice versa.