Bullying is a social problem characterized by intentional aggression over time, usually in school contexts and in cyberspace, characterized by intentionality, repetition, and power asymmetry. Aim: This study aimed to evaluate a health education program for students at preparatory school regarding bullying Research design: A quasi-experimental research design was used in this study. Sample: Simple random sample include 150 students. Setting: Hudaa Sharawy, El-kholafaa El- Rashedeen and El-Shaheed Ahmed Hamdy preparatory schools. Tool for data collection: one tool included four parts, 1st part includes socio-demographic characteristic, 2nd part assesses students’ knowledge about bullying 3rd part assess the effect of bullying on students’ health status, 4thpart students reported practice. Results: it revealed that 87.3 % of the studied sample had good knowledge post program while only10% of them had good knowledge preprogram. 86 % of the studied sample had total satisfactory health practices post program while 64.7% of them had total satisfactory health practices preprogram Conclusion: the student’s total knowledge &total practice about bullying improved after apply program than preprogram. Recommendations: Periodic prevention program and reorientation sessions about bullying for school students.