The need to mainstream biodiversity into economic growth and development is being increasingly recognised and is now also firmly embedded in the Sustainable Development Goals. Drawing on experiences and insights from 16 predominantly megadiverse countries, this report examines how biodiversity is being mainstreamed in four key areas: 1) at the national level, including national development plans and other strategies, institutional co-ordination and national budgets; 2) the agriculture, forestry and fisheries sectors; 3) in development co-operation; and 4) the monitoring and evaluation of biodiversity mainstreaming and how this could be improved.