Sustainable management of renewable resources is often complicated by diversity and dynamic nature of the ecological and socioeconomic systems involved. As these system dynamics and interactions are highly complex and frequently unpredictable, there is a need to opt for transdisciplinary research addressing adaptive and integrated renewable resource management. Companion Modeling (ComMod) is a multi-agent systems (MAS)-based approach relying on synergistic effects between Role-Playing Games (RPG) and Agent-Based Models (ABM) to facilitate information sharing, collective learning, and exchange of perceptions to support negotiation, facilitate collective decision-making, and to strengthen adaptive resource management capacity. Iterative and adaptive sequences of field work and modeling activities allow inclusive and interactive participation of stakeholders during design, implementation, calibration, and validation steps of the models, as well as joint use to explore possible future scenarios. ComMod was implemented in a study of a conflict between two ethnic communities and a newly proposed national park in Northern Thailand. Deforestation, biodiversity conservation, and livelihoods were key issues discussed during RPG sessions, and subsequently represented in an ABM simulator. Consequently, local stakeholders learned about agro-ecological and socioeconomic dynamics and gained an increased awareness of these key issues. Mutual understanding was improved, and the importance of collaborative discussion, essential to negotiation and decision-making, became obvious. Finally, this Northern Thailand experience has shown that collaborative interactions between researchers and local stakeholders mediated by ComMod tools were supportive of improved communication among the conflicting parties and joint learning for adaptive and integrated sustainable management of renewable resources.