In Africa, forest tenure reform to decentralize forest management from central governments to local communities has been occurring since the 1990s to promote forest conservation, poverty alleviation, and sustainable forest-based livelihoods. African governments and donor organizations continue to invest in community forestry, raising the question of what contributes to "success." The present study examines social, economic, and biophysical factors that contribute to success, or lack thereof, in community forestry in southeastern Tanzania. There, community forest enterprises produce commercial timber from natural stands in community forests certified by the Forest Stewardship Council. We compare success across 14 certified community forests using local criteria, emphasizing total revenue earned because half of this revenue is invested in creating community benefits, which incentivize sustainable forest management. Our methods include financial analysis, analysis of potential linkages between success outcomes and attributes of villages and community forests, key informant interviews, and a survey of forest managers. We found that for community forestry with community forest enterprises that produce commercial timber to be most successful, success factors for both community forestry and small-scale, forest-based enterprises must be present and co-occur. In particular, we highlight the importance of having large community forests with a high natural endowment of merchantable timber species for success. A favorable national policy environment, good governance and support at the community and district government levels, secure tenure, tangible benefits, and long-term technical and financial support from a local organization were also important. In addition, we examine the role of forest certification in contributing to success, finding it does so by reinforcing many other success factors. We draw insights from the Tanzanian case that may be relevant for community forestry elsewhere in Africa where community forest enterprises producing commercial timber operate or are desired.