This study aimed to investigate the prevalence of cyberbullying and factors in cyberbullying perpetration with a national sample of 4000 adolescents selected through multi-stage cluster sampling. The respondents were 2166 boys (54.1%) and 1834 girls (45.9%) in 7th12th grades at 24 middle and 24 high schools across South Korea. Statistical analyses of the survey data are summarized as follows. First, 34% of the respondent students were involved in cyberbullying as bullies (6.3%), victims (14.6%), or both bullies and victims (13.1%). Boys had a higher percentage of cyberbullying perpetration than girls. Second, variables for time spent on chat services and Social Network Services (SNS), the experience of being cyberbullied, and offline bullying perpetration tended to increase the probability of students being perpetrators of cyberbullying. However, the cognitive empathy variable contributed to decreased cyberbullying perpetration behaviors. Third, the variables of parental attachment and satisfaction with school life had little impact on perpetration of cyberbullying. These results were discussed to improve the understanding of the characteristics of cyberbullying among Korean adolescents and the youth population in general, while providing educators and researchers information on cyberbullying with practical consideration to its prevention. Boys had a higher percentage of cyberbullying perpetrations than girls.Girls exerted relational violence through chat services more than boys did.The cognitive empathy variable contributed to decreased cyberbullying perpetration behaviors.Cyberbullied experiences were positively related to cyberbullying perpetration.