Hubris is a tendency of leaders to hold an overly confident view of their own capabilities and to abuse power for their own selfish goals, sometimes with disastrous consequences for organizations. A major reason for hubris is the rigorous selection process leaders typically undergo. This study proposes a governance mechanism used successfully in history to tackle hubris: partly random selections, which combine competitive selections by competence with lotteries. A frequently voiced concern about the use of lotteries is that it takes no account of the competence of the leader chosen. We propose that partly random selections can mitigate the disadvantages of both competitive selections alone and lotteries alone and reduce hubris in leaders. We conduct a test of this governance mechanism by means of a computerized laboratory experiment. Our results show that partly random selections significantly reduce the hubris of group leaders.