Thesis advisor: Robert J. Starratt / Despite its provision of sustained, targeted, job-embedded professional development to teachers, instructional coaching, which school districts across the United States have introduced in efforts to midwife instructional improvement, has occasionally suffered the same fate as countless other attempts at school reform. While programs of instructional coaching have endured and become institutionalized in many districts, they have been discontinued in others. Additionally, while the literature reports that instructional coaching in this country originated, and has remained popular, in urban school districts, it is all-but-silent about programs in suburban settings. The present, qualitative research study examined three suburban school districts in efforts to answer the following research question: How do suburban school districts' unique contexts impact the implementation, maintenance, and success of their instructional coaching programs? Case studies of three suburban school districts in Massachusetts were assembled from data collected during semi-structured interviews with twenty-two educators from across the three districts. Resulting data were analyzed across cases through the lens of complexity science, in order that the three school districts, and their programs of instructional coaching, could be explored - if not completely understood - in all their complexity. This investigation found that, while the roll-out of a district's instructional coaching program need not have been a grand event, it was nevertheless essential for faculty members to understand the rationale for the establishment of the program and the role to be played by their schools' coaches. It confirmed assertions in the existing literature that trust is an essential ingredient in any instructional coaching program. It also served to confirm that administrators contribute to the success of instructional coaching programs when they are actively engaged in supporting them. This investigation found, further, that instructional coaching programs, and the schools in which they function, demonstrate key aspects of complex systems. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Lynch School of Education. / Discipline: Education.