This document discusses building multisectoral nutrition systems in Africa through the African Nutrition Security Partnership (ANSP). It provides an overview of ANSP's objectives to reduce stunting through policy development, capacity building, information systems, and scaling up interventions. It then discusses conceptualizing multisectoral nutrition as a complex system and presents tools and strategies for building functional multisectoral nutrition structures, including sensitizing concepts, knowledge brokering, and lessons learned across countries.