Bullying is a major public health concern affecting the lives of many children and adolescents. Therefore, the present study aimed to evaluate the effect of behavioral program in reducing bullying among primary school students. Subjects and methods: a quasi-experimental pretest and posttest design was utilized with sample of 60 of bullied students who had high bullying levels from fifth and sixth grade four governmental primary school in Zagazig city. The data collecting tools composed of two parts: Socio- demographic data and bullying scale among primary school students. The study results revealed the prevalence of bullying among the student in the study school were 39%, highly statistically significant improvement were found between before and after the program regarding knowledge of bullies' students about bullying. Also, there was a highly statistically significant improvement were found before and after the behavioral program regarding total mean score of bullying domains. The study concluded that the behavioral program is effective in reducing bullying among primary school students. Therefore, it is recommended to implement the developed program on a wider scale in the study setting and similar one to confirm its positive effects and to reach more generalizable findings.