Glacier thinning and retreat in the Himalayas has resulted in the formation of new glacial lakes and the enlargement of existing lakes due to the accumulation of meltwater behind loosely consolidated end moraine dams. Such lakes are inherently unstable and can be subject to catastrophic drainage (glacial lake outburst flood or GLOF), which is a potential source of danger to people and property in the valleys below them. Equally, glacial lakes are an important potential natural resource for water supply, which has yet to be effectively investigated. This publication describes the results of a systematic and comprehensive study of the status of glacial lakes and glacial lake outburst flood (GLOF) risk in Nepal, including the vulnerability of downstream people and property and field studies of three of the most critical lakes. The assessment is intended to provide information for use in GLOF risk management in Nepal, as well as describing a detailed stepwise approach and methodology that can be applied throughout the Hindu Kush-Himalayan region. Region-wide cooperation is needed to develop a more coordinated approach and lay the foundations for a glacial lake outburst risk reduction policy.