Prior studies demonstrated that cyberbullying victimization is associated with mental health in adolescent samples. The purpose of this study was to examine the mediational roles of intrusive and deliberate rumination in the association between cyberbullying victimization, depression, and posttraumatic stress symptoms (PTSS) among Chinese adolescents in two-wave longitudinal data. A total of 661 Chinese junior high school students completed the measures at Time 1 (T1) and Time 2 (T2). Adolescents' self-reports of cyberbullying victimization, rumination, depression, and PTSS were used in the analyses. The results showed that cyberbullying victimization was a positive predictor of depression and PTSS through the mediating variable of intrusive rumination, and revealed that deliberate rumination partially mediated the relationship between cyberbullying victimization and depression.