| Professional development allows teachers to create professional knowledge and increase collaboration and collegiality to promote quality teaching and leadership. Peer coaching is frequently overlooked as a form of professional development. The purpose of this quantitative study was to examine the effect of participation in a voluntary peer-coaching team program at a K-12 private, independent school, to address a recognized lack of peer and cross-divisional collaboration and collegiality. The study investigated the perceived impact of peer coaching on collaboration, collegiality, teacher effectiveness, and organizational leadership. The frameworks for the study consisted of learning organization theory, the learning community model, constructivist theory, and the theory of social learning. Data about teacher effectiveness and teacher leadership were collected through an online, researcher-designed survey. Although all 55 faculty members were invited to participate, only 12 completed the online survey in its entirety. A regression analysis was conducted on participant responses to the 69 Likert-type questions, and a thematic analysis was conducted on the 5 short response questions. Teachers who participated in peer coaching experienced more collaboration and collegiality. Furthermore, successful peer-coaching teaming showed a positive, statistically significant relationship to teacher's perceptions as effective educators, in spite of the small sample. These findings support positive social change in that successful peer coaching teams can potentially transform a school culture by engaging faculty in teacher-directed professional development that can improve professionalism, leadership, collegiality, collaboration, teaching, and student learning through a more collaborative model. |