This paper examines agrarian issues in civil wars in Côte d'Ivoire and Sierra Leone. Attention is paid to two different ways in which lineage society evolved during the colonial and post-colonial periods. The motivations of fighters are related to these different trajectories of agrarian social change. In Côte d'Ivoire youth militia fought to uphold a lineage-based social order, but in Sierra Leone a comparable group of young fighters sought to overturn it. Large migrant populations on a forest frontier are an important factor in Côte d'Ivoire, while in Sierra Leone significance attaches to an excluded agrarian underclass. Not all African conflicts are ethnic conflicts; autochthony is shown to be a factor in one conflict and class in the other. Approaches to post-war reconstruction based on undifferentiated notions of community should be resisted.