People differ in their tendency to be grateful, and this affects interpersonal dynamics. Previous research found that individuals with high (versus low) levels of dispositional gratitude exhibited more prosocial behaviors. In this study we demonstrate that dispositional gratitude may also be associated with negative responses toward others. Specifically, we examined the link between dispositional gratitude and condemnations of various moral transgressions. Given that moral norms might be culture-specific, we recruited participants from the U.S., the UK, and China (N = 593 in total) to test potential cultural moderators. Results showed that the higher people scored on dispositional gratitude, the more morally wrong they evaluated transgressions to be, and the more punishment they thought that transgressors deserved. The associations were robust across moral domains, countries, and perceived levels of societal tightness. These findings underscore the pervasive and differentiated impact of dispositional gratitude in interpersonal relations, as it may not only increase prosocial behavior but also intensify negative responses to others who violate moral norms.