Cyberbullying (CB) has recently become a significant issue in today’s society. Given the myriad negative consequences to the cyber-victim, it is important to determine what variables predict CB frequency. Based on broader psychological and communication theory, I predict that anonymity will (a) directly predict CB frequency, (b) moderate the relation between positive attitudes toward CB and CB frequency, and (c) mediate the relation between instant messaging frequency and CB behavior. Participants (N = 181) completed measures designed to assess these aforementioned variables. Results showed that positive attitudes toward CB, CB reinforcement, and anonymity strongly predicted CB frequency. Furthermore, moderation tests confirmed that CB was highest when positive attitudes and anonymity were both high. Finally, mediation tests revealed anonymity mediated the relation between instant messaging frequency and CB behavior. These results are important at elucidating what variables predict CB to hopefully inform intervention efforts aimed at reducing CB.