Three experiments demonstrated that the experience of power leads to an illusion of personal control. Regardless of whether power was experientially primed (Experiments 1 and 3) or manipulated through manager-subordinate roles (Experiment 2), it led to perceived control over outcomes that were beyond the reach of the power holder. Furthermore, this illusory control mediated the influence of power on several self-enhancement and approach-related effects found in the power literature, including optimism (Experiment 2), self-esteem (Experiment 3), and action-orientation (Experiment 3), demonstrating its theoretical importance as a generative cause and driving force behind many of powers far-reaching effects. A fourth experiment ruled out an alternative explanation: that positive mood, rather than illusory control, is at the root of powers effects. The discussion considers implications for existing and future research on the psychology of power, perceived control, and positive illusions.