Over 60 years of research on participative leadership has documented the many benefits of power sharing in organizations. However, a common obstacle to power sharing is the unwillingness of those with power to share it. An experimental study is presented that investigated the effects of managers' implicit theories of power in organizations on their willingness to share power with subordinates. The study proposed that chronic differences in implicit power theories (the degree of competitive vs. cooperative beliefs and ideals regarding organizational power relations) would affect managers' decisions to share or withhold power. Subliminal priming was predicted to temporarily enhance the accessibility of these differences in implicit power theories, thereby fostering or inhibiting spontaneous decisions to share power. Results indicate that the subliminal priming of competitive theories of organizational power negatively influenced managers' immediate, spontaneous decisions to share power, whereas chronic differences in their implicit theories similarly affected their more systematic decisions to share power. The theoretical and applied contributions of the study are discussed.