We examine the social impacts of reservoir construction and management on communities located downstream from four hydropower projects in central Laos using the sustainable livelihoods framework to categorise and quantify impacts across environmental, financial, physical, human and social domains. Hydropower projects had profound impacts on the livelihoods of riparian households living downstream of the case study dams. Many were positive. Employment, social programs and infrastructure development were direct benefits. Indirect benefits included improvements in tourism and hospitality facilities as a consequence of hydropower project infrastructure such as access roads. For most case study households, these beneficial impacts outweighed adverse impacts on riverine fisheries. Minimising negative impacts and maximising the potential benefits requires that the construction, operation, and direct and indirect relations of the project operator with the communities meet appropriate standards of social responsibility. Policy implications of the research for hydropower policy in Laos, such as conditioning development, are discussed.