During the past decade, numerous intervention studies have been published on the effectiveness of programs to promote active living; however, few studies have addressed the dissemination of effective physical activity interventions. Both community settings and healthcare settings are important locations for dissemination of evidence-based programs and policies. A major gap in the existing literature involves the appropriate methodologic approaches for planning, evaluating, and reporting on dissemination efforts for effective and promising interventions in these locations. To address this gap, two hypothetical dissemination studies are presented: a quasi-experimental study of local health agencies (Scenario 1) and a group-randomized trial of clinical practices (Scenario 2). These studies help to elucidate the barriers and opportunities for implementing evidence-based physical activity interventions across different settings. Based on the scenarios, the existing literature, and the authors' experience, dissemination challenges that researchers and practitioners may experience (i.e., issues of design, measures of outcomes and external validity, the balance between fidelity and adaptation to local settings, and the review and funding of dissemination science) are discussed. Researchers, practitioners, and policymakers are invited to address the issues outlined in this article in order to bridge the gap between the generation of new knowledge on efficacious physical activity interventions and widespread application of these approaches in community and clinical settings.