This article applies a capability approach to examine how children's agency, well-being and participation rights can be developed and supported in educational settings. We introduce Amartya Sen's concepts of agency and well-being freedoms and achievements to highlight the tensions and trade-offs between risks to children's agency and well-being in and through educational processes. We draw upon selected empirical examples to illustrate this relationship further. By positioning the development of children's agency as an explicit and important goal of education, alongside well-being achievement, we aim to broaden the evaluative space for assessing what constitutes quality in children's education. We conclude with some reflections on implications for policy and practice going forward.