1. What were the practices teacher leaders used to support instructional change?
2. In what ways did school-level factors shape the practice of the teacher leaders?
The Common Core Standards for Mathematics and Next Generation Science Standards were adopted by states with the goal of preparing students with knowledge and skills needed for college, careers, and citizenry. Adopting these standards necessitated considerable changes in instructional practice. While teacher leadership is known to be important for instructional change, there is little research that articulates the processes through which that influence occurs, and how contextual factors constrain or support those processes. This paper provides a case study of efforts in the Chicago Public Schools to promote widespread instructional change around standards reform through a teacher leader model using retrospective from 2013 to 2017 interviews with 16 math and science teacher leaders serving grades 6–12, along with quantitative analysis of district-wide data showing patterns of change and professional learning. It builds off prior research to articulate a framework of how teacher leaders promote instructional change.