Evidence suggests that natural resources have driven conflict and underdevelopment in modern Africa. We show that this relationship exists primarily when neighboring regions are resource-rich. When neighbors are resource-poor, own resources instead drive economic growth. To motivate the empirical study of this set of facts, we present a simple model of parties engaged in potential conflict over resources, revealing that economic prosperity is a function of equilibrium conflict prevalence, determined not just by a region’s own resources but also by the resources of its neighbors. Structural estimates confirm the model’s predictions, and reveal that conflict equilibria are more prevalent where institutional quality is worse.