A collaborative school-based intervention aimed at modifying relationships among administrators and teachers was implemented in three middle and junior high schools. Across the intervention schools, teachers were active collaborators in identifying problems and then articulating and implementing customized interventions to redress those problems. Analyses of both teacher (N=180) and student (N=2,631) data provide support for positive outcomes. Teachers' perceptions of school climate improved, and longitudinal models suggested that these improvements mediated the impact of treatment on teacher reports of affiliation and academic focus. In addition, the treatment had a positive impact on teachers' perceptions of principal support, which led to improvements in teacher attitudes. Furthermore, students in the intervention schools reported improvements in school climate relative to students in the comparison schools. Taken together, these results suggest that a strategy of encouraging and supporting teacher-led interventions, customized to the needs and circumstances of each particular school, can successfully revitalize school settings, leading to improvements not only in school's climate, but also in the quality of interactions within the settings. (Contains 3 tables and 2 figures.)