Cyber bullying appeared simultaneously with the emergence of information, technology. The consequences of cyber bullying are not serious less than the traditional forms of violence. Violence occurs in all subjects, from junior to high , school students. The purpose of research: Research on bullying rates of high school students in Hanoi. Research Methodology: Questionnaire based on cross-sectional study. Results: Figure out 823 pupils from two h1gh schools in Hanoi. The rate of being bullied is 31.2 percent. The rate of bullying other students is 34.8 percent. Internet usage time is larger than 5h/day and 6 days/week. The subjects in the study had certain knowledge of cyber bullying. Conclusions and Recommendations: The rate of cyber bullying is quite high in Hanoi. Thus, it is needed to be controlled and educated seriously.