This article describes an actor-focused approach to creating a theory of change that is context-specific, grounded in an understanding of local historical, cultural, linguistic, and social realities, and inspired by a commitment to social justice in education reform. In 2019, the authors completed a research evaluation of the Government of Cambodia's inaugural Multilingual Education National Action Plan designed to increase inclusion of Indigenous children in basic education. The project mandate included constructing a theory of change. Using the participatory approach of Outcome Harvesting, data were obtained about behavioral changes among actors implementing and affected by the plan. Qualitative data analyses identified 115 behaviors distributed across 15 categories of actors in the education system, and uncovered assumptions and experiences of change processes and relationships. The authors created a generic theory of change mandated by the commissioning body for the evaluation. It was unidirectional and institution-centered, focused on objectives, strategies, outputs, and outcomes. To provide a more nuanced, inclusive, context-specific and potentially useful representation of change processes, the authors drew upon the behavior change data to construct a second, actor-focused theory of change. Additionally, the authors constructed a third theory of change showing education strategies in the current context compared to internationally accepted best practice in multilingual education. This study illustrates a focus on manifest behaviors and relationships among actors in theories of change. Actor-focused frameworks that describe situationally specific, participatory action and reciprocal learning can promote inclusive, sustainable, systems-level change toward children's right to meaningful quality basic education.