Three experiments were conducted to test how moral punishment is affected by deliberation. The intuitive-morality view predicts that moral punishment should increase under time pressure and decrease with deliberation. Moral punishment was examined in a simultaneous one-shot Prisoner’s Dilemma game with a costly punishment option. The players cooperated or defected and then decided whether or not to punish their partners. In Experiment 1, the punishment decisions were made under time pressure or under no time pressure. In Experiment 2, the punishment decisions were delayed by pauses in which participants deliberated their decisions or worked on a demanding distractor task. In Experiment 3, participants were asked to deliberate on fairness or on their self-interests before deciding whether to punish their partners. Different types of punishment were distinguished using a multinomial model. In Experiment 1, time pressure decreased moral punishment. In Experiment 2, deliberation increased moral punishment. However, Experiment 3 showed that the effect of deliberation depended on the topics that were deliberated. When participants thought about their self-interests rather than about fairness, cooperation and moral punishment decreased and antisocial punishment increased. The results suggest that spontaneous deliberation increases moral punishment but the effects of deliberation are modulated by the type of deliberation that takes place.