New thinking on the nature of fragility and risk shows a shift from a one-dimensional understanding of fragility towards a more holistic approach in which degrees of fragility exist on a spectrum. This approach recognises the need for collaborative, regional and global solutions to tackle the root causes - and that acknowledges the need to broaden the use of institutional influences, policy levers and expertise “beyond aid”. In parallel, many development co-operation agencies are working to meet commitments under the newly agreed Sustainable Development Goals, the Paris Agreement on climate change, and the Addis Ababa Action Agenda on financing sustainable development. In this context, the OECD Development Assistance Committee (DAC) commissioned a study on how to work more effectively in fragile, at-risk and crisis-affected contexts. This report identifies 12 lessons grouped into 3 thematic areas: building institutional fitness, aspiring to deliver change, and leaving no-one behind. These lessons are illustrated with a wealth of good practice examples from DAC members.