In recent years, bullying victimization has received increasing attention from researchers worldwide. The link between bullying victimization and reactive aggression is well-established in numerous studies. However, longitudinal association and underlying mechanisms remain less explored. This study examined gender-specific effects of traditional and cyberbullying victimization on reactive aggression using longitudinal data from 486 Chinese primary and middle school students (51.44% boys, average age = 11.66 ± 1.66 years). Assessments occurred every six months across three waves. Structural equation modeling and multigroup analyses were used to test mediating effects and gender differences. Depressive symptoms mediated the association between traditional bullying victimization and reactive aggression, but no such mediation was observed for cyberbullying victimization. Gender differences were also found ([delta]CFI = 0.03, [delta]RESEA = 0.01). These findings underscore the importance of gender-specific interventions and supportive environments for addressing offline and online bullying.