This study examined the impact of superiors’ ethical leadership on subordinates’ unethical pro-organizational behavior (UPB) and the mediating effects of followership. The research subjects were officials from the ten central departments of the South Korean government, and a cross-sectional survey was conducted among them. Overall, 404 questionnaires were used in the empirical analysis. Multiple regression analysis and Hayes Process Macro were used to validate the research hypotheses, which examined the relationship among ethical leadership, followership, and UPB. The results are as follows: First, the relationship between ethical leadership and followership was statistically significant. Second, the study showed that followership had a statistically significant effect on UPB but not ethical leadership. Third, testing the hypotheses regarding the mediating effect of followership on the relationship between ethical leadership and UPB revealed statistically significant results. This study confirms that followership significantly influences UPB and suggests that ethical leadership is an important precedent factor of followership. The study concludes with the theoretical and practical implications of these findings, along with the study’s limitations.