Although national History testify from ancient cities, urbanization rate in Lao PDR remains quite low compared to Asian countries; furthermore, the population of the main urban centers (national capital and second-rank border cities located along the Mekong River) appears lower than same-rank cities in neighboring countries. Transformed during and after the colonization area, these Laotian cities are facing a new phase of urbanization since the 1990’s. The implementation of regional cooperation frameworks such as the Greater Mekong Subregion (GMS) is indeed likely to give more functions to cities located near an international border, even if these cities were so far excluded of international flows due to their position in the urban hierarchy. Under this economic and institutional context, Lao PDR second and third ranks cities are currently transformed by an internationalization process, characterized by rising cross-border flows and the empowerment of transnational stakeholders. The case study in this contribution focuses on Savannakhet and Houay Xay, both located on GMS economic corridors. Even if these cities are different from a demographic, economic or administrative point of view, they are both facing an unprecedented level of internationalization that induces a transformation of their spatial organization at the urban scale with the creation of new internationalized forms such as cross-border infrastructures or special economic zones.