Quality teaching and learning are vital to meet the increasingly complex needs of students as they prepare for further education and work in the 21st century. This publication provides insights on how to create sustainable and high quality teacher capacity development systems in primary and secondary education, technical and vocational education and training, and higher education programs. It showcases 13 case studies from around the world as examples of teacher professional development programs that support, improve, and harness teaching capabilities and expertise. The publication also discusses government initiatives and other factors that can contribute to quality teaching.