This paper examines the emerging trends and patterns of merchandise trade in Southeast Asia and their implications for growth and structural changes in domestic manufacturing, with emphasis on the on-going process of global production sharing. The analysis reveals that participation in global production networks (GPNs) has strengthened economic interdependence among the Southeast Asian countries, and between these countries and China and the other major economies in East Asia, but this has not lessoned the dependence of growth dynamism of these countries on the global economy. The operation of the regional cross-border production networks depends inexorably on trade in final goods with North America and the European Union. Reflecting differences in policy regimes and the overall business climate, the degree of integration within GPNs and the resultant impact on industrial upgrading varies notably among the countries in the region.