To improve teaching and advance student learning requires weaving together the curriculum that students engage with every day with the professional learning of teachers. This paper is designed as a resource for system leaders at the district, state, and charter-management organization (CMO) levels looking to improve instructional outcomes for students by improving teacher development in their schools. Part I briefly describes the research base for this argument. Part II examines three cases of innovative practice and identifies ways in which a state department, a district, and a group of enterprising teachers are leading positive change efforts. Part III identifies key considerations and enabling conditions system leaders should prioritize when organizing professional learning around high-quality curriculum.