To assess Vietnam’s water security, it is necessary to develop a framework along with the indicators for evaluating the water security index (WSI). The water security assessment framework is based on the selection of indicators according to the SMART, KPI criteria, and the WSI framework proposed by several international organisations and scientists around the world, taking into account the characteristics of water resources in Vietnam, including the key factors affecting water security and data, accommodatable data for the calculation requirements, scale, and level of detail. The article presents a framework for assessing water security in Vietnam (national scale, region, river basin, and province/city). At the same time, the authors have provided a method and illustrated how to identify a number of key indicators (or indices) in the water security framework as the basis for assessing Vietnam’s water security.