Why fertility declines is still a matter of intense debate. One theory proposes that fertility decline may be partly driven by shifts in parental investment strategies: couples reduce family size as demographic and economic changes cause investment in the quality of children to become more important than investment in the quantity of children. A key driver for this change is a shift from a subsistence-based to a skills-based economy, in which education enhances child quality. Evolutionary anthropologists have modified this theory to propose that parental investment will diverge during the demographic transition according to resource availability: couples with the greatest access to resources will invest more in quality than in quantity of children. Here we test the impact of resources on educational investment in two populations on the cusp of fertility decline: the patrilineal Arsi Oromo of Ethiopia and the matrilineal Chewa of Malawi. In both populations, increased wealth is associated with greater biases in the allocation of education between children. In richer families, early-born children are prioritized over later-born ones, although early-born sons are favored in the patrilineal population and early-born daughters in the matrilineal population. Poorer families invest less in their children's education but also discriminate less between children. © 2010 by The Wenner-Gren Foundation for Anthropological Research. All rights reserved.