A joint FAO/CDE publication examines one of the least-known environments in the world. Dryland mountains are of great strategic value to regional and global development – they provide 90% of the freshwater supply to surrounding dry lowlands – and yet they are often overlooked by decision- and policymakers. Dryland mountains are of great strategic value to regional and global development. They provide up to 90% of the freshwater supply to surrounding dry lowlands. More than a quarter of the world’s biodiversity hotspots and six out of eight Vavilov Centres of Diversity are found in dryland mountains. Yet these mountain regions are under increasing threat from climate change and unsustainable forms of land use, including mining and tourism. The UN Convention to Combat Desertification and the Mountain Partnership both provide important frameworks to mobilize governments, international agencies, NGOs and other stakeholders for greater attention and support. This publication presents the socio-economy and environment of dryland mountains, the current threats they face, and good practices in sustainable development. It concludes with key messages for policy- and decision-makers.