Cross‐Border Lesson Study for STEM Teacher Development: Experiences of Research Collaborations Between Japan, Chile, Brazil, and Costa Rica

This article explores international collaboration in cross‐border Lesson Study groups as a form of collaborative action research that improves teaching and learning in mathematics, science, and technology. Using an analytical framework of international collaboration, two experiences of the authors from the last decade involving academics from Japan, Chile, Brazil, and Costa Rica are analyzed, considering different levels of professional development for primary school teachers in both initial and continuing education. From this perspective, cross‐border Lesson Study is considered both a professional development approach and a tool for intercultural collaborative research that facilitates the exchange of visions, practices, and challenges. The analysis shows that cross‐border Lesson Study functions as a robust methodological infrastructure for collaborative action research in STEM education, strengthening professional teacher learning, improving student‐centered teaching, and producing empirical knowledge in diverse international contexts.