This chapter characterizes and evaluates the internationalization process on going for twin cities located across the Thai-Lao border and on the Greater Mekong Subregion (GMS) corridors. Two corridors implemented within the Asian Development Bank (ADB) GMS framework at the beginning of the 1990s have a great importance for Thailand and Lao PDR, i.e. the North South Economic Corridor (NSEC) linking Bangkok to Kunming via Lao PDR or via Myanmar's Shan State, and the East West Economic Corridor (EWEC) linking Moulmein port in Myanmar to Danang port in Vietnam via Thailand and Savannakhet Province in Lao PDR (cf. Taillard, Map 2.2 in this volume).

The “twin cities” can be defined according to multiple criteria. The first characteristic used for this article is the fact that the selected cities are border towns, i.e. located on an international border (the Mekong River between Thailand and Lao PDR) and with some functions directly related to the presence of this border. Furthermore, the other criterion used is a geographic one, implying the existence of two urban centres facing each other on each side of this international border. If they can be linked by an institutional agreement (“twin cities” or “sister cities” agreement), this institutional aspect is an optional requirement, compared to the interactions (formal and informal) existing between the two cities. Finally, the expression “twin cities” should be nuanced as it implies a resemblance or symmetry between the two urban centres, which is limited in reality, in terms of population, urban landscape or economic activities.

This chapter will try to discuss this theoretical frame by studying an example of these so-called “twin cities”, Mukdahan and Savannakhet, focusing on their characteristics, functions and interactions.

Since the end of the 1980s, development of border regions has been supported by national governments as well as international institutions such as the ADB to promote decentralization and enhance cross-border trade and economic cooperation with neighbouring countries (Maneepong 2010, p. 1). In the case of Thailand, border towns have been identified as economic gateways since the 7th National Plan, established for the 1992–96 period (NESDB 1999). For Lao PDR, the largest border towns have been developed under the ADB Secondary Towns project at the end of the 1990s.