This chapter explores the expanding instructional leadership responsibilities of principals. It discusses how teacher leaders are essential to success in achieving accountability for the learning of all students. The chapter provides three principles that support a framework for principals' actions. Three principles are leadership through relationships, leadership requires distributed power and authority, leadership for professional learning. Whereas the old models of leadership may have encouraged building the capacity of a single person, specifically the campus principal, the problems facing education require principals and teacher leaders to work side by side as a community of practitioners. Building positive relationships, distributing power and authority, and aligning teacher leadership with teacher learning focus the principal's actions on increased teacher leading and learning. Hirsh and Hord, "the most significant factor in whether students learn well is quality teaching". Even as legislators mandate quality professional development opportunities for teachers, there are too few schools or school systems where this type of professional learning exists.