This is a story about teachers engaging in mathematics teacher leadership. The focus is on the teachers' learning, and the purpose is to illuminate the process. The setting is a semester-long graduate class called Teacher Leadership in Mathematics Education, and the characters are elementary and middle school teachers. Those in this group did not serve as designated leaders in their schools; they were not instructional coaches or curriculum coordinators. They were classroom teachers who had developed new insights about mathematics teaching and learning and were eager to use those insights to influence the learning of their school colleagues. This article describes how a research-based framework helped these teachers break through the noise of myriad initiatives and focus on the crucial aspects of math education in the context of leadership.