Teachers are in a very real sense the embodiment of leadership, providing direction, guidance, and feedback to their students in addition to acting as role models. Teachers may well thus benefit from developmental coaching that draws on theories of leadership. This study was both an experimental (randomly assigned conditions) and a quasiexperimental (pre-post) study. A randomized controlled design was used to explore the impact of coaching on goal attainment, mental health, workplace well-being, and resilience, and a quasi-experimental (pre-post) design was used to explore the impact of coaching on leadership styles. Forty-four high school teachers were randomly assigned to either coaching or a waitlist control group. The coaching used a cognitive-behavioral, solution-focused approach and was informed by theories of self-leadership and transformational leadership. Participants in the coaching group received multirater feedback on their leadership style and undertook 10 coaching sessions conducted by professional coaches over a 20-week period. Compared with randomly allocated controls, participation in coaching was associated with increased goal attainment, reduced stress, and enhanced workplace well-being and resilience. Pre-post analyses for the coaching group indicated that coaching enhanced self-reported achievement and humanisticencouraging components of constructive leadership styles and reduced self-reported aggressive/defensive and passive/defensive leadership styles. Findings suggest that coaching, as a professional development methodology, has great potential to contribute to the development and well-being of society beyond the corporate and organizational settings with which leadership coaching and executive coaching are normally associated.