Introduction: divorce as a socially detrimental phenomenon cause children’s depression after parents’ separation, so children of divorce react negatively to this problem. The aim of this study is to investigate the effectiveness of Group Cognitive- Behavioral Therapy (GCBT) in reducing depression for children of divorce in Tehran Welfare Centers.Methods: The study was carried out in a quasi-experimental framework in which pretest, posttest and control group were designed. The sample which was selected by availability sampling method included 20 girls of divorced parents who resided in two Welfare Centers in Tehran. by Using Children’s Depression Inventory (CDI) by Maria Kavacs (1977), it was revealed that all subjects suffered depression (as they gained high scores), so these Centers were randomly assigned into experimental and control groups. The experimental group received training- treatment program for 8 sessions, each of which the lasted an hour and finally all applicants filled in pre- and posttest. Research hypotheses were tested by Analysis of Covariance (ANCOVA).Results: Statistical analyses indicated that the post-test scores have been affected by the independent variable (F=94.263, P<0.05, Sig (2-tailed) =P- value=0.00<0.05=a), also total mean score and standard deviation of CDI in experimental group decreased from 20.80 and 6.941 in pretest to 10.90 and 2.469 in post-test. In addition, the mean and standard deviation of CDI in control group changed form 21.20 and 5.391 in pretest to 21.50 and 5.338 in posttest, which showed no statistically significant difference.Conclusion: The results of study indicated that Group Cognitive- Behavioral Therapy (GCBT) had been effective in reducing depression and feeling of incompetency and in capability in children of divorce.