In 2016 the United Nations Office for Disaster Risk Reduction (UNISDR) commissioned the development of guidelines on national disaster risk assessment (NDRA) as part of a series of thematic guidelines under its “Words into Action” initiative to support national implementation of the Sendai Framework for Disaster Risk Reduction 2015-2030. The present Guidelines are the result of the collaboration between over 100 leading experts from national authorities, international organizations, non-governmental organizations, academia, think tanks and private-sector entities. They focus on Sendai Framework’s first Priority for Action: Understanding Disaster Risk, which is the basis for all measures on disaster risk reduction and is closely linked to the other three Priorities for Action.