Anonymity is considered a key motivator for cyber aggression, but few investigations have focused on the connection between anonymity and the subsequent engagement in aggression through the cyber context. The present longitudinal study utilized structural equation modeling to reveal indirect associations between two types of anonymity (i.e., punishment by authority figures and retaliation from the target) and later cyber aggression among 130 young adults. These relationships were examined through the influence of beliefs about not getting caught and not believing in the permanency of online content. Findings indicated that both forms of anonymity were related to cyber aggression 6 months later through two explanatory mechanisms (i.e., confidence with not getting caught and believing online content is not permanent), after controlling for gender and cyber aggression at Time 1. The implications of these findings are discussed, and an appeal for additional research investigating cyber aggression among young adults is given.