This Operational Research and Impact Evaluation (ORIE) Research Summary outlines the approach, key findings and conclusions of a review of literature on the prevalence and determinants of child and maternal undernutrition in northern Nigeria, and direct and indirect interventions to tackle undernutrition, globally and in Nigeria, undertaken in 2012. The aims of the evidence review were to: assess gaps in knowledge; support the design of the WINNN and ORIE programmes; review interventions to address undernutrition in Nigeria and globally; and inform DFID on possible pilots to tackle underlying determinants of childhood stunting in northern Nigeria. Evidence Graph of Undernutrition in Northern Nigeria Click on graph to see interactive version