The Greater Mekong Subregion comprises Cambodia, the People's Republic of China (PRC, specifically Yunnan Province and Guangxi Zhuang Autonomous Region), Lao People's Democratic Republic (Lao PDR), Myanmar, Thailand, and Viet Nam.

In 1992, with assistance from Asian Development Bank (ADB), these six countries entered into a program of subregional economic cooperation, designed to enhance economic relations.

With support from ADB and other donors, the Greater Mekong Subregion (GMS) Program supports the implementation of high-priority subregional projects in agriculture, energy, environment, health and human resource development, information and communication technology, tourism, transport, transport and trade facilitation, and urban development.

To realize its vision of a prosperous, integrated, and harmonious subregion, the GMS program has adopted a three-pronged strategy (the 3 Cs):

• Increasing connectivity through sustainable development of physical infrastructure and the transformation of transport corridors into transnational economic corridors.
• Improving competitiveness through efficient facilitation of cross-border movement of people and goods and the integration of markets, production processes, and value chains.
• Building a greater sense of community through projects and programs that address shared social and environmental concerns.

Substantial progress has been achieved in implementing GMS projects since 1992. More than $20 billion in investments have been directly channeled through the program.

The subregion’s abundant natural resources provide both income and sustenance to the majority of people in the GMS who still subsist, in whole or part, on agriculture. Mekong nations are increasingly shifting from subsistence farming to more diversified economies, and to more open, market-based systems. In parallel with this trend are the growing commercial relations among the six GMS countries, particularly in terms of cross-border trade, investment, and labor mobility. Natural resources, including water for hydropower, agriculture and fisheries, as well as timber, petroleum, and minerals, continues to significantly contribute to the subregion’s growth.

The GMS embraces flora and fauna that have expanded northward along the Malay Peninsula into Thailand – and onward to the Himalayan foothills – and have advanced along the broad river valleys as dry deciduous forests, similar to those of India. Ten million years of changing sea levels have left a rich legacy of unique life forms that have evolved in isolation on the Cardamom and Annamite mountains of Cambodia, Lao PDR, Thailand, and Viet Nam.

The rich human and natural resource endowments of the Mekong region have made it a new frontier of Asian economic growth. Indeed, the Mekong region has the potential to become one of the world's fastest growing areas.