Background: Frameworks such as the WSCC model provide evidence-based guidance for addressing school health at the school, district, and regional level. However, frameworks do not implement themselves; they require the mobilization and collaboration of stakeholders within communities and an understanding of the unique resources and barriers within each context. Furthermore, addressing school health presents a complex systems problem. Methods: Community-based system dynamics (CBSD) is a participatory approach for engaging communities in understanding and changing complex systems. We used a descriptive multiple case study design to evaluate how and why CBSD was used as a tool for stakeholders to engage with the complexity of school health. Results: We analyzed 3 cases to understand how these methods were used to enhance collaboration, analysis, and community action at multiple levels, including in 2 school districts, with a city-wide stakeholder committee, and with a group of high school students. Conclusions: Community-based system dynamics presents a promising approach for building shared language and ownership among stakeholders, tailoring to local community contexts, and mobilizing stakeholders for action based on new system insights. We close with a discussion of unique opportunities and challenges of expanding the use of CBSD in the field of school health.