What happens when teachers start to observe each other's classes? How do teachers make meaning of observing and being observed? What effects, if any, does requiring peer observation have on the teaching community? This research explores these questions in a qualitative study of peer observation of teaching (POT) in the 2nd-12th grades of an independent day school in a city in the northeastern United States. Peer observation as a school-wide practice was part of a new academic initiative to review curriculum and pedagogy in grades two through twelve. Schon's (1987) theory of reflective practice and Cochran-Smith & Lytle's (2001) theory of inquiry stance frame the analysis of the data collected. This study is situated in the research on peer observation and leadership, mentoring, teacher learning, collaboration, and professional development. Surveys, interviews, reflective journals, and archival materials are analyzed to understand the effects of peer observation on the individual teachers. The findings of this study have implications for fostering teacher leadership and agency within a school community. Including POT as part of a comprehensive professional development program, created by and for teachers, can ground professional development in teacher reflection, shared conversation and inquiry into practice and privileges teacher input in the review of curriculum and pedagogy. Supporting regular, consistent POT practice among teachers has the potential to shift a community--from one of teachers working as isolated islands to one characterized by supportive peer relationships and strong curricular cohesion and coherence. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]