Theoretical reflections suggest that avengers and targets of revenge have self-serving perception biases when judging the severity of revenge acts and preceding offenses. Empirical research investigating such biases has so far focused on either the offense or the revenge act and may have confounded a perception bias with a situational selection bias (i.e., avengers and targets selecting different events in self-serving ways, so that there may be actual, as opposed to perceptual, differences in severity). The current research circumvents this shortcoming by empirically investigating this perception bias by assessing avengers’ and targets’ severity scores of both the offense and the revenge act, and comparing these scores with severity scores of independent raters. Results show that although there is a situational selection bias, there is also a perception bias for both avengers and targets: Both avengers and targets believe that the other person's act is worse than their own act. This perception bias may explain the existence of perpetuating revenge cycles.