Cultural differences in aggression are still poorly understood. The purpose of this article is to assess whether a tool for measuring aggression has the same meaning across cultures. Analyzing samples from Spain (n=262), US (n=344) and Hong-Kong (n=645), we used confirmatory factor analysis to investigate measurement invariance of the refined version of the Aggression-Questionnaire (Bryant & Smith, 2001). The measurement of aggression was more equivalent between the Chinese and Spanish versions than between these two and the American version. Aggression does not show invariance at the culture level. Cultural variables such as affective autonomy or individualism may influence the meaning of aggression. Aggressive behavior models can be improved by incorporating cultural variables