The number of nuclear reactors approaching decommissioning, or already in the process of decommissioning, is increasing globally. Planning and performing decommissioning and dismantling activities raises different safety challenges compared to steady state electricity generation. As a result, decommissioning experience is growing worldwide, but there can be a tendency to focus primarily on the technical aspects of the work, and less on the human aspects. With regard to human and organisational factors (HOF), the principal challenges and solutions will depend on the decommissioning strategy. Nuclear organisations approaching decommissioning will need to adapt in accordance with the chosen strategy, and will need to address the issue of organisational change. Since there are many common challenges related to HOF and safety, it is worth discussing and sharing experience on how to deal with these challenges. This report addresses HOF for all phases, including the transition from generation operations to end of generation, defueling, decommissioning, and dismantling of nuclear facilities. It also provides practical guidance on integrating the identified key organisational capabilities within new or existing organisations required for effective and safe nuclear decommissioning. The report discusses the safety challenges in decommissioning, the phases of decommissioning, and the human and organisational challenges associated with the transition from generation operations to decommissioning. While the report focuses primarily on nuclear, radiological, and conventional safety, it is important to note that similar considerations also apply to environmental safety. Relevant learning and topical case studies from global decommissioning activities are included where available to help inform organisations in their endeavours in this area by sharing good practice and experience.