The present study investigated the psychological profile of 430 Greek university students who reported cyber-bullying/victimization experiences. Participants completed a self-report questionnaire, measuring cyber-bullying, cyber-victimization, internet frequency and use, personality characteristics, and psychological symptoms. Results indicated that 58.4% of the sample had participated in a cyber-bullying incident assuming any role. Cyber bully/victims, the most common participant role, endorsed more psychological symptoms, more psychopathic traits, and were high sensation seekers, compared to the rest of the groups, whereas cyber-victims scored higher on empathy. Cyber-bullying was predicted by callous/unemotional and impulsive/irresponsible traits, depression, Internet use, as well as lack of social skills. The latter four variables also predicted cyber-victimization along with gender. Findings are discussed in terms of prevention and intervention strategies.