Lesson Study is a rapidly growing and increasingly popular teacher professional development approach and is valued for its cyclical, classroom-based and collaborative nature. Mostly used in primary and secondary education, Lesson Study has only recently been applied to the context of initial teacher education focussing on pre-service teachers' professional learning. Only a few studies report on teacher educators participating in Lesson Study. This study aims to fill this gap by examining to what extent Lesson Study is considered a valuable approach to support teacher educators' professional learning and what conditions should be taken into account when applying Lesson Study in their context. Two groups of teacher educators were followed using learning reports as they participated in a Lesson Study cycle. To determine whether the reported reflections sustained in their practice, focus group interviews were held one year after their Lesson Study participation. The results show that, depending on the conditions, participating in Lesson Study can be supportive as a means to focusing on the learning of pre-service teachers, exchanging knowledge and experiences, and counteracting a culture of professional isolation.