Governments are increasingly devolving governance of natural resources from central administrations to subnational levels. Researchers routinely document the complexity and contradictions of this process, but policy prescriptions and their underlying theoretical models remain overly simplified. Going beyond classical statements in the policy literature that emphasize interjurisdictional competition, we draw on recent developments in the multidisciplinary literature on institutional theory and the growing stock of research on natural resource governance. We develop an “institutional mediation” approach, which emphasizes the multilevel nestedness of rules and highlights the role of institutional incentives, contradictions, and complementarities in shaping how actors navigate decentralization reforms. Brief case studies of decentralization of forest governance in Bolivia and Uganda lend initial credence to the claims of this approach, and preliminary hypotheses for further research are proposed.