Objective-Leadership in organizations is important in shaping workers' perceptions, responses to organizational change, and acceptance of innovations, such as evidence-based practices. Transformational leadership inspires and motivates followers, whereas transactional leadership is based more on reinforcement and exchanges. Studies have shown that in youth and family service organizations, mental health providers' attitudes toward adopting an evidence-based practice are associated with organizational context and individual provider differences. The purpose of this study was to expand these findings by examining the association between leadership and mental health providers' attitudes toward adopting evidence-based practice.Methods-Participants were 303 public-sector mental health service clinicians and case managers from 49 programs who were providing mental health services to children, adolescents, and their families. Data were gathered on providers' characteristics, attitudes toward evidence-based practices, and perceptions of their supervisors' leadership behaviors. Zero-order correlations and multilevel regression analyses were conducted that controlled for effects of service providers' characteristics.Results-Both transformational and transactional leadership were positively associated with providers' having more positive attitudes toward adoption of evidence-based practice, and transformational leadership was negatively associated with providers' perception of difference between the providers' current practice and evidence-based practice.Conclusions-Mental health service organizations may benefit from improving transformational and transactional supervisory leadership skills in preparation for implementing evidence-based practices.There is growing momentum and pressure to move evidence-based mental health interventions into real-world practice settings (1-5). Most of these practice settings involve a relationship between a clinical or case management supervisor and practitioners who provide services. Often in community settings the clinical supervisor also supervises work activities, including conducting performance appraisals and other human resource functions. Leadership is important in these activities. Recent work has also demonstrated that mental health service providers' attitudes toward adopting evidence-based practice are associated with organizational context (for example, structure and policies) and individual provider differences (for example, education and experience) (6,7). Yet, although leadership is held to influence the adoption of innovations, such as evidence-based practices (8), there has been little research on the association between leadership of the mental health supervisor and staff attitudes toward adopting evidence-based practice. However, some more general leadership studies have been conducted.Leadership research is pervasive in the organizational literature, and studies in mental health services suggest that leadership is important for both for the organizational proces...