This paper examines ethnic diversity and local public goods in rural western Kenya. The identification strategy relies on the stable historically determined patterns of ethnic land settlement. Ethnic diversity is associated with lower primary school funding and worse school facilities, and there is suggestive evidence that it leads to poor water well maintenance. The theoretical model illustrates how inability to impose social sanctions in diverse communities leads to collective action failures, and we find that school committees in diverse areas do impose fewer sanctions on defaulting parents. We relate these results to the literature on social capital and economic development and discuss implications for decentralization in less developed countries.