Research from the past two decades positions relational trust as a key factor in school reform efforts. Trust between teachers and their principal (teacher-principal trust) and teachers and their colleagues (teacher-teacher trust) are particularly important. "Leading Together" (LT) is a new professional development and coaching model of the Center for Courage & Renewal designed to develop individual and collective capacity to build trust and enhance communication among adults in schools. In this article, we investigate the relation between successful implementation of LT and changes in trust in eight schools that participated in a pilot study of LT from 2012 to 2014. Results showed moderate increases in teacher-principal trust and teacher-teacher trust in schools implementing LT successfully. This article describes changes in trust and processes needed for the successful implementation of team-implemented programs, models, or approaches. [For the corresponding grantee submission, see ED580950.]