Moral licensing refers to the effect that when people initially behave in a moral way, they are later more likely to display behaviors that are immoral, unethical, or otherwise problematic. We provide a state-of-the-art overview of moral licensing by conducting a meta-analysis of 91 studies (7,397 participants) that compare a licensing condition with a control condition. Based on this analysis, the magnitude of the moral licensing effect is estimated to be a Cohen’s d of 0.31. We tested potential moderators and found that published studies tend to have larger moral licensing effects than unpublished studies. We found no empirical evidence for other moderators that were theorized to be of importance. The effect size estimate implies that studies require many more participants to draw solid conclusions about moral licensing and its possible moderators.