When teachers work together on matters of instruction, it often, although not always, contributes to their learning about teaching and in turn to improvement in valued school outcomes (Bryk and Schneider 2002; Frank, Zhao, and Borman 2004; Pil and Leana 2009). Teachers’ interactions can foster innovation and the development of new knowledge about teaching (Coburn 2001; Smylie 1995). Though teachers’ interactions about teaching are important to their on-the-job learning opportunities, the nature of these interactions is critical for whether or not they enable learning and improvement (Coburn, 2001; Davis, 2003; Y. Goddard, Goddard, & Tschannen-Moran, 2007; Little, 2003; Spillane, Hopkins, & Sweet 2018). School systems, albeit some more than others, do not leave such matters to chance but instead work to structure teachers’ and school leaders’ on the job interactions about teaching. One of the primary ways in which they do so is by developing and maintaining educational infrastructures. In this paper, we examine the role of school systems’ educational infrastructure in supporting the professional learning of teachers and school leaders based on three empirical studies involving different (e.g., public, private, hybrid) school systems operating in the US. By educational infrastructure, we mean those formal structures and resources that school systems develop and deploy to support teachers’ instructional practice and enable efforts to improve that practice, including curricular materials, student assessments, and procedures and routines for analyzing practice and structuring the work of improvement (e.g., school improvement planning, coaching, mentoring) (Cohen, Spillane, & Peurach,; Spillane, Hopkins, & Sweet, 2018). Using data from these three mixed methods studies, we examine teachers’ and leaders’ on the job professional learning and the role of educational infrastructure therein. Specifically, we consider the role of educational infrastructure in enabling (and constraining) on the job professional learning from the perspectives of teachers, school leaders, and system leaders. Based on our analysis, we identify key challenges and principles for designing educational infrastructures in order to support teachers’ and leaders’ learning from one another on the job. Further, we identify some core dilemmas that school leaders experience as they work to support teachers’ learning from peers on the job and consider how they work to manage, i.e., cope with, these dilemmas.

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