This study establishes the relationship between a manager’s Machiavellian personality and unethical behavior. It also tests the cross-level interaction effects of collectivism and power distance on the relationship between a Machiavellian personality and unethical behavior. The multi-level and multi-source data are collected from 22 public sector organizations from which 202 responses from managers about their personalities, power distance, and collectivism, and 626 subordinates’ ratings of the managers’ unethical behavior were received and used. The results show that Machiavellian personality has a positive relationship with unethical behavior. The cross-level interaction effects also show that cultural dimensions such as power distance, and collectivism—significantly and positively moderate the relationship between Machiavellian personality and unethical behavior. Based on the study’s findings, implications for theory and practice are offered.