Social capital provides an overview of a community's togetherness, unity, and mutual trust in achieving common goals towards sustainable development. Community forest management requires a certain level of social capital for sustainable forest management. This study aims to identify and analyze key factors influencing the community's social capital in forest management. The key factors influencing the level of social capital in a community include internal factors such as individual characteristics and knowledge of community forest management, and external factors such as extension activities, the role of the forest farmer group, and access to information. Using the theoretical framework of social capital and multiple linear regression models, we found that social capital was significantly influenced by both internal and external factors, indicating a need to improve these factors. To increase the value of social capital for maintaining the sustainability of community forest management, the results of this Indonesian case suggest that individual characteristics, procedural knowledge of community forest management, and the role of forest farmer groups need to be considered for forest management based on the social capital of forest communities.