The drought in the Horn of Africa and the protracted conflict has created a humanitarian emergency that has led to a declaration of famine in several regions of Somalia and the Somali region of Ethiopia. As a result of depleted water resources, widespread internal displacement, malnutrition, and inadequate water and sanitation facilities, cholera outbreaks have occurred. This Evidence Synthesis asks two questions: a) what are the practices, behaviours, social norms and wider factors that increase the risk of cholera/AWD transmission among communities in Somalia and the Somali region of Ethiopia? and b) what beliefs and other socio-economic factors influence the decision to seek treatment for cholera/AWD (for adults, adolescents and children) from health facilities in Somalia and the Somali region of Ethiopia? To answer these questions, the author explores the determinants of risk and vulnerability to cholera in the Somali regions, and then examines behavioural factors that increase the risk of cholera transmission, followed by the contextual factors that shape treatment-seeking.