Meditation has been advocated as a mental practice designed to reduce suffering and increase virtuous behavior. Although it has been previously linked to altruistic acts, its ability to reduce aggression and related retributive behaviors remains open to question. Here, we report on an experiment in which participants were randomly assigned to a mindfulness meditation or active control condition 3 weeks prior to facing a real-time provocation known to evoke aggression. Participants’ capacities for executive control were also assessed subsequent to training. Results showed that 3 weeks of daily meditation practice substantially reduced aggressive behavior even in the absence of any enhanced executive control capabilities. These results suggest that meditation attenuates aggression through direct reductions in motives to cause harm to others.