Sustainable environmental management requires a decision support approach that accounts for dynamic connections between social and ecological systems, integrates stakeholder deliberation with scientific analysis, incorporates diverse stakeholder knowledge, and fosters relationships among stakeholders that can accommodate changing information and changing social and environmental conditions. Participatory system dynamics modeling provides such a framework. It supports stakeholder learning about the system and the perspectives of other stakeholders, and can help build social capital among stakeholders. Four cases of participatory system dynamics modeling, which range from no to full participant involvement in model development, support the idea that greater social capital development results from greater participation in model development, but also suggest that even the simplest use of simulation models in a group fosters stakeholder learning about the system through surprise and discovery. To maximize the learning value of simulation models, it is important to allow enough time for debriefing the “aha!” moments that lead to curiosity about system behavior. To maximize social capital development, it is important to build enough time into the problem structuring and model conceptualization phases for stakeholders to articulate their mental models and examine those of other participants.