Teachers' professional lives and their role in change efforts have always been central to the Journal of Educational Change. Articles have addressed teachers' motivation for and commitment to reform, their belief systems, their professionalism, their networks, and their professional development, among other topics. Unequivocally, teachers are central to educational change. In this article, I will reflect upon my own work over the past 20 + years as a lens through which to examine this topic, and drawing out implications for research, policy, and practice. The common threads across this work include issues of agency, power, and social justice that have influenced the role of teachers in various waves of reform. I discuss teacher agency in reforms ranging from bottom-up change efforts to externally developed comprehensive school reform models and those that rely on teacher collaboration and participation as research partners.