The Asian Development Bank (ADB) is one of the most influential development institutions in the Greater Mekong sub-region in the push to build large-scale infrastructure including hydroelectric dams. Controversies over big dams in Asia have unveiled the lack of effective governance mechanisms through which all stakeholder interests can be taken into account in resource management decision making. In the case of the Theun-Hinboun hydropower project in Lao PDR, the actions of the ADB have showed inadequacies regarding the project decision making and implementation processes although the project has been economically successful and the ADB has enhanced the country’s capacity build-up. The aim of the article is to review the history of the Theun-Hinboun project and identify areas that need to be strengthened recognizing future planning needs, and to identify important future lines of study at Theun-Hinboun. Good governance can be enhanced by institutionalizing participation at the project, district, provincial and national levels including improving inter-agency coordination. An institutional mechanism, which ensures that revenue from the export of hydropower is actually used for poverty alleviation, is needed.