Facing many challenges and operating under limited resources, schools attempt to reach multiple ambitious goals. Since the late 1990s, accountability policies from the state and federal levels have placed districts and schools under heavy pressure to improve student outcomes on standardized tests (Diamond 2007; Honig and Hatch 2004). Principals are now required to serve as managers and visionaries as well as instructional leaders (Rigby 2014; Woulfin and Weiner 2017). Increasingly, while working towards instructional improvement, school systems and their administrators distribute leadership and delegate tasks, especially those related to issues of curriculum and instruction, to teachers and instructional coaches. In this way, teacher leaders are major participants in systems of distributed leadership. Thus, teacher leadership matters in school change.

Instructional coaches, department chairs, and team leaders engage in teacher leadership (Gabriel and Woulfin 2017; Little 1995). They carry out multiple forms of work, ranging from planning and coordinating with other teachers to attending district-sponsored professional development sessions. They take on work that administrators may have previously conducted. Despite the designation as leader, teacher leaders’ work is nonsupervisory in nature. That is, teacher leaders do not evaluate teachers and typically hold little regulative power. Wenner and Campbell (2017) encourages researchers, reformers, and practitioners to ‘consider teacher leaders as not just influencing individual teachers, but also having the capability to influence the entire school, community, and profession’ (p. 140). This broad definition of teacher leaders’ reach hinges on the notion that ‘teachers are uniquely positioned to promote change within schools because they are well versed in the complexities involved with teaching’ (Wenner and Campbell 2017:134).

Yet teacher leadership should not be treated as a new phenomenon. This is because teachers have long served as grade level team leaders and department chairs. However, teacher leadership is expanding, with many districts and states creating structures and formal roles for teacher leaders (Berry 2017; Little 2003). More importantly, teacher leadership is transforming as school systems attempt to attain challenging goals during the accountability era (Boyd-Dimock and McGree 1994; Little 2003). In the past, teacher leaders’ roles were limited in scope and defined by principals or other administrators (Boyd-Dimock and McGree 1994; Little 2003). In contrast, as Berry (2017) highlights, ‘more opportunities are slowly but surely becoming available for teachers to lead policy and pedagogical reforms, from both inside—and outside—school systems’. This indicates that many of today’s teacher leaders hold power over different facets of schooling and community engagement and enact ideas emanating from administrators, intermediary organizations, and professional associations.

In today’s education policy environment, teacher leadership is also treated as a strategy to retain quality teachers. Reformers and administrators presume that teacher leader positions help form a career ladder in the teaching profession that can retain quality teachers in the school system (Darling-Hammond 2003). Thus, while remaining in classrooms, teacher leaders can take on alternative roles as professionals with the voice – and power – to advocate for change at the school and system levels. The availability of such positions as a retention strategy can also be viewed as a strategy for improving student outcomes. For example, teacher leadership career pathways may increase the number of experienced teachers within the teaching force, decrease the number of teachers who leave the profession within the first 5 years, and increase the volume of mentoring and teacher-led instructional improvements. Like other complex strategies for improving the education system, understandings and instantiations of teacher leadership are multiple and varied. After defining teacher leadership, this entry reviews existing research on teacher leadership and discusses opportunities and challenges in its enactment.