Introduction: The present study examined the effects of group assertive training on social anxiety, social skills and academic performance of female freshmen in Bahmaei high school. Method: The related population includes all freshmen in Bahmaei high school in 2008 . The sample includes 60 students selected by random multistage sampling method. They were randomly divided into experiment and control groups. The instruments used in this study were Watson & Friend's Anxiety Scale and Eisler & Miller's Social Skills Rating Scale. The research design was pretest- posttest with the control group. For analyzing the data MANOVA method was used. Results: The Results of MANOVA showed that, at least there is a significant difference between two groups in one of the dependent variables. Then, the significant difference between two groups in all three dependent variables was then confirmed by ANOVA method. Conclusion: Group assertive training increased social skills and school performance and decreased social anxiety of experimental groups in compare with control groups.