["Review of Development Economics, EarlyView. ", "\nABSTRACT\nThe second sustainable development goal aims to eradicate all forms of undernourishment in the world by 2030. Despite the progress that has been made in the fight against hunger, the number of people languishing under the weight of a food crisis is still growing. This calls for an urgent need to re‐examine the determinants of undernourishment. This paper investigates whether and how economic complexity affects the prevalence of undernourishment in developing countries. Using a panel of 51 developing countries, our results consistently show that greater economic complexity—reflecting the capacity to produce and export sophisticated, knowledge‐intensive goods—significantly reduces both overall and child undernourishment. The effect remains robust across alternative measures of complexity, institutional controls, and alternative estimation approaches. Mediation analysis shows that the reduction in undernourishment operates mainly through higher income and employment generated by complex production structures. These findings highlight the developmental value of industrial diversification and knowledge accumulation for achieving the “Zero Hunger” goal in developing countries. The study contributes to the emerging literature linking economic complexity to human development outcomes, offering novel evidence that structural transformation can also improve food security.\n"]