Fires are increasingly responsible for forest degradation in the humid tropics due to the expansion of fire-dependent agriculture, fragmentation, intensive logging practices and severe droughts. However, these forest fires have been largely overlooked by negotiations for Reducing Emissions from Deforestation and Degradation (REDD+). This paper examines how forest fires affect REDD+ schemes by compromising carbon permanence; undermining the potential of sustainable forest management and reforestation and regeneration activities in tropical countries; and threatening the additional benefits that can be accrued from REDD+, including biodiversity conservation and rural poverty alleviation. Narrowly focusing on avoiding deforestation, the sustainable management of forests or regeneration schemes will not always guarantee protection from fire occurrence, and investments in tropical forests may ultimately fail to achieve long-term emission reductions unless they also reduce the risk of forest fires. Integrating forest fire reduction into REDD+ presents many challenges, requiring: changes in agricultural practices that take place outside of the remaining forests; the monitoring and prediction of spatio-temporal patterns of forest fires across whole biomes; guarantees of additionality; avoiding leakage of fire-dependent agriculture; ensuring that responsibilities for fire management are fairly distributed; protection for rural livelihoods; and that any new activities result in positive outcomes for local people.