Session 1: Conditions leading to the success of the mathematics research community are contrasted with the case of mathematics teaching at all levels. Session 2: This session will take up Sybilla Beckmann’s call to create a community of all mathematics teachers, and will examine lesson study as one possible means to accomplish this. The session will present recent research on the impact of lesson study on both teachers’ and students’ mathematical knowledge, drawing on data from a recent randomized controlled trial. The session will explore the role of high‐ quality mathematical materials in lesson study, and will illuminate models of university‐school collaborative lesson study from Japan as well as the United States. It will focus on the progress that has occurred in the US, and the challenges that remain, to create a community of all mathematics teachers.