Wormith, J. Stephen2007-01-012013-01-042007-01-022013-01-042007-012007-01-02January 20http://hdl.handle.net/10388/etd-01012007-202524Adolescents’ intentions to behave in both reactive and instrumental aggression were assessed using the Theory of Planned Behaviour (TPB; I. Ajzen, 1985). Along with examining the TPB, perceptions of self-efficacy (A. Bandura, 1982) towards both types of aggression were also assessed. Self-report questionnaires were administered to 162 grade 10 to 12 students in two independent school districts. Using Path Analysis, the TPB was shown to significantly explain both instrumental and reactive aggression. In the context of reactive aggression, attitudes were found to have the greatest influence on intentions to behave aggressively. As for instrumental aggression, self-efficacy was found to have the greatest influence on intentions. Overall, the results of this study provide support for using the TPB to explain adolescent aggression. In addition, this study further demonstrates the value of distinguishing between reactive and instrumental functions of aggression.en-USaggressionTheory of Planned Behaviourself-efficacyadolescentstext