The aim of this study is to examine the awareness levels of high school administrators about cyberbullying behaviours. The study was conducted with 403 school administrators working in public high schools in the 2017-2018 academic year. In addition to “personal information form”, “Cyber Bullying Behaviour Manager Awareness Questionnaire” developed by Serin (2012) on the basis of literature was used in the study. The administrators were asked to read the text containing the definition of cyberbullying before answering the questionnaire and they were asked to answer the questions in the questionnaire according to this definition. The administrators were asked questions about whether they had previously heard about the concept of cyberbullying, whether they had witnessed such behaviour in the schools they served. According to the findings obtained from the study, it was found that 68.5% of high school administrators had previously heard the concept of cyberbullying and 53.1% of administrators had known the definition of this concept. When administrators were asked to estimate the percentage of students studying between nine and twelve grades engaging in cyberbullying behaviours in their schools, this rate was found to be 54.1% for all administrators. In the same way, when the school administrators were asked to estimate the rate of cyber victimization of the students attending their schools, this rate was found to be 45.4% for the administrators. 58.6% of the school administrators stated that the behaviours related to cyberbullying were the highest in the tenth grade. 23.3% of the administrators stated that cyberbullying behaviours were the highest in the eleventh grade, 11.7% in the ninth grade and 6.5% in the twelfth year.