This article examines a model of professional development called “video clubs” in which teachers watch and discuss excerpts of videos from their classrooms. We investigate how participation in a video club influences teachers’ thinking and practice by exploring three related contexts: (a) teachers’ comments during video-club meetings, (b) teachers’ self-reports of the effects of the video club, and (c) teachers’ instruction across the year. Data analysis revealed changes in all three contexts. In the video-club meetings, teachers paid increased attention to student mathematical thinking over the course of the year. In interviews, teachers reported having learned about students’ mathematical thinking, about the importance of attending to student ideas during instruction, and about their school’s mathematics curriculum. Finally, shifts were also uncovered in the teachers’ instruction. By the end of the year, teachers increasingly made space for student thinking to emerge in the classroom, probed students’ underlying understandings, and learned from their students while teaching.

The articles in this volume reflect the continued popularity of video in professional development and raise important questions about how to situate video productively in varied contexts. Together, they highlight the complexity of expanding video-based professional development beyond designers and the challenges that designers and facilitators experience as they prepare others to lead teacher learning in these settings. In this commentary, we examine how these papers advance research on facilitation of professional development, with a particular focus on the issues for using video productively with teachers. We conclude by raising several issues for future research.