This research indicates that a critical factor for understanding the success or failure of anti‐violence campaigns is the aggressiveness of the target audience. We propose that person and situation interact in predicting post‐intervention attitudes toward violence, fighting expectations, and intentions to learn how to use real guns. Across two studies conducted in different countries and with different age populations, we found that anti‐violence campaigns were effective, only for those for whom the message was already pro‐attitudinal (low trait aggressiveness). In contrast, for individuals with relatively higher scores in trait aggressiveness, there was no difference in attitudes toward violence between those who received the anti‐violence intervention and those assigned to the control group. In fact, the anti‐violence messages resulted in a boomerang effect, increasing the favorability of attitudes toward violence in one of the studies. Aggr. Behav. 42:471–482, 2016. © 2016 Wiley Periodicals, Inc.