This paper presents the development and validation of a reflective log designed for researching and supporting teachers’ relational agency for change. Drawing on theories of teacher agency and inclusive pedagogy, relational agency is defined as teachers working inclusively and collaboratively with families, colleagues and other professionals to address barriers to learning experienced by some students, while avoiding their marginalisation. The log is designed collaboratively with practitioners to analyse these ways of working in relation to particular purposes of change that matter to them, including but not limited to enhancing student achievement. Following responses from 24 teachers and 22 student teachers about the purposes and nature of their collaborative practices within and beyond school, a draft log has been adjusted for uses in future research and professional reflection.