Ethical leadership predicts important organizational outcomes such as decreased deviant and increased organizational citizenship behavior (OCB). We argued that due to the distinct nature of these two types of employee behaviors ethical leadership decreases deviance in a linear manner (i.e. more ethical leadership leading to less deviance) but we expected ethical leadership to reveal a curvilinear relationship with respect to OCB. Specifically we expected that at lower levels ethical leadership promotes OCB. However at high levels ethical leadership should lead to a decrease in these behaviors. We also examined a mechanism that explains this curvilinear pattern that is followers' perceptions of moral reproach. Our predictions were supported in three organizational field studies and an experiment. These findings offer a better understanding of the processes that underlie the workings of ethical leadership. They also imply a dilemma for organizations in which they face the choice between limiting deviant employee behavior and promoting OCB.