This study examines if parental neglect is significantly associated with adolescent cyberbullying perpetration, and whether this relationship is mediated by smartphone addiction. In addition, the moderation of self-regulation in the direct and indirect effects of parental neglect on cyberbullying perpetration among adolescents is determined. A random sample of 728 Chinese adolescents from Grade 10 to 12 in senior high schools respond to anonymous questionnaires regarding parental neglect, smartphone addiction, self-regulation and cyberbullying perpetration. The data are then analysed using macro PROCESS. Results reveal that adolescents who are neglected by parents are more likely to engage in cyberbullying perpetration. Smartphone addiction significantly partially mediates the above relationship. Moreover, self-regulation not only moderates the relationship of cyberbullying perpetration with parental neglect but also its association with smartphone addiction among adolescents. This study contributes to a better understanding of how parental neglect increases the risk of adolescent cyberbullying perpetration, which may be reduced through tailored interventions.