resentment or hurt done by others either one or a few people directly, to persons who are not able to fight.This study was to dertemine the representation of knowledge about bullying at SMP Negeri 11 Yogyakarta and SMP Muhammadiyah 3 Yogyakarta. The study was a descriptive cross sectinal. The samples in this study were 280 respondents who were students in VII and VIII class in SMP Negeri 11 Yogyakarta and SMP Muhammadiyah 3 Yogyakarta. The sampling technique were using simple random sampling. This research was conducted in April-May 2016 in SMP Negeri 11 Yogyakarta and SMP Muhammadiyah 3 Yogyakarta. The result in both school showed that bullying knowledge in SMP Negeri 11 Yogyakarta as many as 87 respondents (70.2%) had a good knowledge, 23 respondents (18.5%) had fair knowledge and 14 respondents (11, 3%) had less knowledge. Knowledge of bullying at SMP Muhammadiyah 3 Yogyakarta as many as 94 respondents (60.4%) had a good knowledge, 36 respondents (23.1%) had a fair knowledge and 26 respondents (16.7%) had less knowledge. SMP Negeri 11 Yogyakarta and SMP Muhammadiyah 3 Yogyakarta has a good knowledge about bullying. With this result the respondents are expected to maintain and reimprove knowledge related to bullying.