We investigated whether altruistic justification increases cheating behavior while suppressing its associated physiological arousal. In the first study (n = 60), participants strategically employed altruistic considerations to justify their dishonesty and promote their personal goals. In the second study (n = 110), participants who worked to benefit others (compared to participants who worked to benefit themselves) cheated more and were less likely to be detected by a lie detector test. In addition, among participants who worked to benefit others, more honest participants experienced higher psychological distress than dishonest participants. These findings suggest that physiological arousal may be a good indicator of self-interest cheating, but not a justified one.