This study bridges teacher leadership research with principles of co-design in an effort to understand teachers' experiences with co-design as a process of teacher leadership and its implications for strengthening teacher leadership development efforts. Using qualitative data from a multi-year co-design research project aimed at developing curricular materials, we explore how co-design aligns with and promotes multiple dimensions of teacher leadership. Findings revealed that teachers not only engaged in a process that shaped how they saw themselves as leaders, but also that critical elements of co-design promoted teacher leadership enactment.