Objectives: The purpose of this study was to investigate the effectiveness of storytelling on aggression in 6 to eight-year old boys. Method: Using a Quasi experimental, pretest-posttest follow-up design with control group, a sample consisting of 22 elementary school boys who had scored one standard deviation above the mean on Shahim Aggression Scale, were randomly assigned to two groups. The experimental group underwent 11 sessions of “storytelling” as the independent factor, and the control group received no intervention. Upon the completion of intervention and after three months, both groups were tested to determine the effect of the independent factor on the dependent factor of “aggression”. Data were analyzed using repeated measures analysis of variance. Results: Both parents and teachers reported that storytelling reduced the signs of aggression in children. This decrease remained stable in the three-month follow-up. Conclusion: These findings indicate the efficiency of stories and their structure in educating children and solving their problems.