Social cognitive theory adopts an agentic perspective in which individuals are producers of experiences and shapers of events. Among the mechanisms of human agency, none is more focal or pervading than the belief of personal efficacy. This core belief is the foundation of human agency. Unless people believe that they can produce desired effects and forestall undesired ones by their actions, they have little incentive to act. The growing interdependence of human functioning is placing a premium on the exercise of collective agency through shared beliefs in the power to produce effects by collective action. The present article analyzes the nature of perceived collective efficacy and its centrality in how people live their lives. Perceived collective efficacy fosters groups’ motivational commitment to their missions, resilience to adversity, and performance accomplishment.