Farmers and herders in arid regions of Africa are highly exposed to climate stresses, especially drought. However, adaptation to climate change is not only a biophysical or technical problem, it also involves social challenge. Although communities in semi-arid zones have organised their livelihoods around uncertainty, climate predictions indicate that new extremes will be a real challenge to their capacity to adapt. This report looks at local social institutions in Ethiopia and Mali and their role in adaptation. It finds that these institutions mediate people’s adaptive processes, production practices, land and water governance, social support systems, gendered household dynamics, use of weather and climate information, and interactions with external actors and interventions. Adaptation is a long-term transformation and efforts that build on or complement existing adaptive processes and institutions stand a better chance of being both materially and socially effective.