Extant research has uniformly demonstrated that leader humility is beneficial for subordinates, teams, and even organizations. Drawing upon attribution theory, we challenge this prevailing conclusion by identifying a potential dark side of leader humility and suggesting that leader humility can be a mixed blessing. We propose that the effects of leader humility hinge on subordinates' attributions of such humble behavior. On the one hand, when subordinates attribute leader humility in a self-serving way, leader humility is positively associated with subordinate psychological entitlement, which in turn increases workplace deviance. On the other hand, when subordinates do not attribute leader humility in a self-serving way, leader humility is positively associated with leader-member exchange, which in turn decreases workplace deviance. We found support for our hypotheses across a field study and an experiment. Taken together, our findings reveal the perils and benefits of leader humility and the importance of examining subordinate attributions in this unique leadership process.