Efforts to devolve rights and engage Indigenous Peoples and local communities in conservation have increased the demand for evidence of the e cacy of community-based conservation (CBC) and insights into what enables its success. We curated a diverse sample of 128 projects reporting both human well-being and environmental outcomes and coded 57 national-level, community-level, project-level, and control variables. We found that over 80% of CBC projects had some positive human well-being or environmental outcomes, but only 32% achieved positive outcomes for both. Applying random forest classi cation, we found that the best predictors of combined success could be distilled to 17 variables representative of various policy levers and actionable opportunities for conservation practitioners related to national contexts, community characteristics, and the implementation of various strategies and interventions informed by existing CBC frameworks. We found that CBC projects had higher probabilities of combined success when they occurred in national contexts supportive of effective local governance, partnered with communities inclined toward collective action, acknowledged con ict or trust issues that could undermine it, promoted economic diversi cation, and invested in various capacity-building interventions, providing important insights into how to encourage greater success in CBC.