Teacher leaders can play an important role in school improvement efforts, but require district support to effectively lead their peers. Partnering with outside organizations is one way that districts can deepen their capacity to support and sustain teacher leadership. In the current landscape of rigorous standards implementation, teacher leadership is gaining increased attention and interest as a school improvement practice. Moreover, the Every Student Succeeds Act calls out teacher leadership as an intervention strategy, and recent research points to effective teacher leaders as a positive influence on teacher professional learning and on teacher retention. However, to be effective, teacher leaders need to be well supported by their districts. In this issue of "CenterView," the Center for the Future of Teaching and Learning describes how districts can foster strong teacher leadership--specifically, the Center highlights the promising strategy of partnering with an outside organization to help develop and sustain teacher leaders districtwide. This issue is the first in a series on teacher leadership for supporting teachers in advancing college- and career-readiness instructional practices.