Background <p>Given the importance and high prevalence of Internet addiction (IA), this study aimed to investigate the relationship between bullying victimization and Chinese adolescent students’ IA and its mechanism—mediated by cyberbullying perpetration and moderated by social support.</p> Methods <p>Participants completed the Internet Addiction Test (IAT) and provided information on their demographics, experiences with bullying, and social support. General linear modeling (GLM), structural equation modeling (SEM), and interaction item analysis were conducted.</p> Results <p>The study included 60,268 middle and high school students with a mean age of 15.9 ± 1.651 years, comprising 45.6% males, 88.7% Han ethnicity, and 82.7% rural residents. Among the participants, 35.1% were classified as having IA, and 14.3% reported experiencing any bullying victimization. We found: (1) Bullying victimization was positively related to adolescent IA, except for physical victims; (2) reduced cyberbullying perpetration positively mediated the relation between social bullying victimization and adolescent IA while negatively mediating the link between physical and cyber victims and IA; (3) the positive moderation roles were observed in the effect of subjective support on the relationship between experiences of being cyberbullied and IA, objective support on the correlation between physical victimization and IA, and utilization of support on the link between social victimization and IA, while objective support negatively moderated the correlation between social victimization and IA.</p> Conclusions <p>The study suggests that cyberbullying perpetration and social support are important factors in understanding the impact of bullying victimization on adolescent IA and underscores the need for improving the quality of bullying interventions and social support for at-risk adolescents.</p>