The objective of the study was to analyze the personal and family variables of cyberbullies. and identify variables that predict cyber-aggression. The sample comprised 3,026 participants from the Basque country, aged 12 to 18 years. Using a predictive design, 8 assessment instruments were administered. The results of the analysis of variance and post-hoc analysis confirm that, compared to those who had not performed any cyberbullying behavior (non-cyberbullies) in the last year, cyberbullies (severe and occasional) had been significantly more frequently bully victims and bullies, as well as cybervictims. and they showed less empathy, friendliness, responsibility, and self-esteem, and higher neuroticism, antisocial behavior, and school problems. Moreover, their parents had a low level of acceptance/involvement in their children's lives. Severe cyberbullies (compared to occasional cyberbullies and non-cyberbullies) had significantly less emotion regulation and social adaptation, and more problems (shyness-withdrawal. psychopathological and psychosomatic symptoms), and their parents used high levels of coercion/imposition, and discipline. Linear regression analysis identified having been a cybervictim as a predictor variable of cyberbullying perpetration in both sexes. In addition, in boys, low empathy, low emotional regulation. high openness and extraversion, as well as having a mother with a high level of coercion/discipline predicted cyber-aggression. In girls, having been a bully and having suffered few bullying behaviors were predictors of the probability of becoming a cyberbully. The study identifies relevant personal and family variables to establish strategies to prevent and reduce cyberbullying from the school and family.