Research on aggression in the West has focused mainly on the dichotomy between proactive and reactive aggression, but not the co-occurring proactive-reactive aggression subtype, despite its prevalence. The authors investigated the differences in psychological and behavioral correlates among proactive, reactive, and proactive-reactive student aggressors and nonaggressors in Hong Kong, China, based on their scores on the Reactive and Proactive Aggression Questionnaire. Participants were 1,356 secondary school students (805 males and 551 females, aged 11 to 18 years). A one-way multivariate analysis of covariance was conducted to examine group differences in aggression, attention deficits, anxiety/depression, and delinquency. Results showed that proactive-reactive aggressors were significantly more aggressive, less attentive, more anxious/depressed, and more engaged in delinquent behaviors. Reactive and proactive aggressors did not differ in three of these four behaviors. Implications for research and practice when working with proactive-reactive aggressors are discussed. (Contains 3 tables.)