Decentralizing natural resource management to local people, especially in tropical countries, has become a trend. We review recent evidence for the impacts of decentralization on the biodiversity values of forests and forested landscapes, which encompass most of the biodiversity of the tropics. Few studies document the impact of decentralized management on biodiversity. We conclude that there may be situations where local management is a good option for biodiversity but there are also situations where this is not the case. We advocate increased research to document the impact of local management on biodiversity. We also argue that locally managed forests should be seen as components of landscapes where governance arrangements favor the achievement of a balance between the local livelihood values and the global public goods values of forests.