In this paper, we argue that the social influence of the group is a supportive medium for older adult thriving. To promote the physical well-being aspect of thriving, we discuss groups as one means of offering social support. We present a specific model of physical activity intervention (i.e., group-mediated cognitive behavioral intervention) that uses deliberately-formed interactive groups to help motivate older adults to engage in and sustain physical activity. Our article includes four sections that concern the GMCB intervention model. The first serves as background as to why groups can be powerful behavior change agents and describes the basic model of group motivated intervention. The second section provides a generic description of the intervention structure and how the GMCB intervention is conducted. The third section presents a meta-analytic summary of results of older adult GMCB physical activity interventions across three levels of outcomes: adherence to physical activity, functional and physiological, and social cognitive. The fourth section concludes with commentary about the translational perspective for the GMCB in the future.