Environmental policies ought to be integrated into economic sectors for successful outcomes. We assess to what extent Reducing Emissions from Deforestation and forest Degradation (REDD +) is integrated into land-use sectors driving deforestation in Cameroon. REDD + governance has been extensively examined, including the challenges of a multisectoral approach to tackle the drivers of deforestation, especially those lying outside the forestry sector. Yet, these studies have focussed on cross-sectoral coordination, giving little attention to factors such as political will and the adequacy of policy instruments for integration. We amend and apply an innovative framework for environmental policy integration to conduct a comprehensive assessment of REDD + policy integration in Cameroon, a Congo Basin country experiencing increasing deforestation rates due to agriculture, husbandry, infrastructure development and mining. Drawing from policy documents and in-depth interviews with key informants, we found out that territorial battles between ministries, insecurity about their understanding of forest matters in different land-use sectors, and dysfunctional policy instruments have undermined REDD + policy integration. Our study suggests that REDD + integration into land-use sectors would be enhanced by informing stakeholders about their roles in the REDD + process, completing and legitimising the forest zoning plan, addressing loopholes in environmental assessment regulations, and alleviating inconsistencies in land-use rules. These instruments would be reinforced with an economic tool internalising carbon costs in projects generating forest emissions.