The objective of the study was to examine how distinct psychopathic traits, including callous-unemotional (CU) traits, impulsivity and narcissism, as well as family, school and friend social support are longitudinally associated with cyberbullying and cyber-victimization. Associations were investigated by employing a four-year longitudinal design in a large sample of Greek-Cypriot adolescents. Findings suggested that cyber-bullying and cyber-victimization decreased from early to middle adolescence. Additionally, the longitudinal model suggested that both CU traits and narcissism, assessed in grade 7, were associated with the onset of cyber-bullying and cyber-victimization in grade 8, but not with change over time. Impulsivity did not predict cyber-bullying or cyber-victimization. Finally, none of the environmental factors were associated with the onset and growth of cyber-bullying, although family support predicted girls' initial levels and change over time in cyber-victimization. Current findings have major theoretical and practical implications for the development of cyber-bullying and victimization.