This publication is the result of a collaborative effort, between the IAEA, OECD Nuclear Energy Agency and European Commission, to develop a standard taxonomy for nuclear facility decommissioning and thereby facilitate the sharing of knowledge on this topic. Adoption of the taxonomy will support the capture of knowledge from the ongoing implementation of decommissioning activities involving nuclear power plants, research reactors, and fuel cycle facilities. This publication will benefit a wide range of professionals working on gathering and organizing knowledge to be shared in the field of decommissioning, including government officials, managers of nuclear facility operating organizations, regulators, and industrial organizations offering decommissioning and waste management services.