Leading school change is a challenging endeavor. Successful leadership requires strategic and sustained effort, particularly in the shifting and uncertain environment of urban public schools. The concept of distributed leadership—in which multiple actors tackle the challenges of school leadership in concert—is a promising way to strengthen professional practice and thereby improve the educational experiences of all students. The Annenberg Distributed Leadership (DL) project was one of the first efforts in the nation to deliberately take on the challenge of designing and implementing a concerted effort to build distributed leadership capacity in a diverse set of urban schools to improve the quality of teaching and learning. The DL project featured the careful selection of leadership team members to identify and lead instructional improvement efforts; ample professional development to build cohesive teams and help members understand the motivational, psychological, and pedagogical aspects of advocating instructional change; resources to apply to the task; and ongoing school-based coaching to guide leadership team efforts. This report describes the Consortium for Policy Research in Education’s mixed-method evaluation of the DL project. The evaluation featured a cluster randomized control trial, where schools first agreed to participate in the study, and then were chosen by lottery to participate in the DL project or serve in the comparison group. Overall there were 16 DL schools and 21 comparison sites in the evaluation.