In a global justice problem, equality of opportunity is satisfied if individual well-being is independent of exogenous irrelevant characteristics. Policymakers, however, address questions involving local justice problems. We interpret a collection of local justice problems as the decentralized global justice problem. We show that controlling for effort locally, which is not required by the global justice objective, is sufficient for decentralizing equality of opportunity. Moreover, under some conditions, equalizing rewards to effort is not only sufficient but necessary. This implies in particular that most affirmative action policies may not contribute to providing equality of opportunity. © (2009) by the Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.