While Action Research (AR) is promoted as a powerful route for teachers' professional development, different contextual challenges may arise during the process; teachers may be helped to overcome these challenges with the guidance of external facilitators. Drawing on data from interviews and the teachers' AR reports, this article explores how two EFL teachers conducted AR by participating in a university-school collaborative project. Findings of the study show that with the scaffolding provided by university researchers, the teachers changed their conceptions about research and coped with different contextual constraints in their AR, leading to professional learning and development. This study concludes with some implications about how AR can be used to promote teachers' continuing professional development.