Despite widespread public attention to cyberbullying, online aggression and victimization have received scant conceptual development. This article focuses on how opportunities for aggression are distinct online from those of offline social contexts. The model developed here is informed by a recent aggression typology, which extends the reactive-proactive distinction by distinguishing aggression based on the affective motive (appetitive vs. reactive) and the recruitment of self-control. This typology informs an analysis of psychological processes linked to individual differences that are relevant to adolescents' aggressive activities. Processes implicated include hostile schema activation, anger and fatigue effects on self-control, anger rumination, empathic failure, excitation transfer, and thrill-seeking. With these processes established, the proposed model focuses on how features of online social platforms may afford opportunities for distinct types of aggression by engaging these processes in adolescent users. Features of online settings that present distinct opportunities for activation of these processes are reviewed for each process, including social cue ambiguity, temporal lag, cue permanence, anonymity, the continual perception of audience, and the availability of online gaming and online pornography. For each of the conceptually grounded cyber-aggression-relevant processes, implications for innovative research directions on adolescent cyber-aggression are presented.