As community-based natural resource management (CBNRM) increases in popularity, the question of the capacity of such groups to successfully manage natural resources becomes increasingly relevant. However, few studies have quantifiably analyzed how the amount or type of capacity in a CBNRM organization directly affects the outputs or the environmental outcomes produced. This paucity of research exists in part due to the diversity of indicators for CBNRM group capacity, as well as the ensuing debate over how to best define and measure success in CBNRM initiatives. Although concrete outputs vary widely, many efforts center on creating natural resource management plans (RMPs). The primary objective of our research was to explore the link between capacity and RMP implementation success, as perceived by practitioners among CBNRM groups across Illinois. A short online survey was constructed, utilizing findings from focus groups in combination with an extensive literature review, to measure CBNRM participants' (n = 190) perceptions of 10 key capacity indicators and RMP implementation success. Results show that capacity perceptions varied significantly among respondents in low, moderate, and high RMP implementation success groups, and that group capacity was predictive of the degree of perceived RMP implementation success. Further, our findings suggest that bonding social capital and outreach are crucial in predicting low versus moderate RMP success, while leadership, motivation, and vision best distinguish the moderately successful and highly successful groups.