Changing clinical practice is hard, and changing practices within larger organizations is even harder. Increasingly, policymakers are looking to implementation science—the study of why some changes prove more durable than others—to understand the dynamics of successful transformation. In this brief, we summarize the results of an ongoing community-academicpartnership to increase the uptake of evidence-based practices in Philadelphia’s public behavioral health care system. Over five years, researchers found that widescale initiatives did successfully change the way care was delivered, albeit modestly and slowly. The evidence suggests that organizational factors, such as a proficient work culture, are more important than individual therapist factors, like openness in change, in influencing successful practice change. Furthermore, organizations must address staff turnover and burnout, and employees must feel supported in general in order for managers to expect them to change. In short, while practice transformation is possible—even in highly stressed and under-resourced public health settings—it requires focusing on underlying problems within organizations as well as championing new policies.