Aim: Peer bullying is thought to be negatively affected by high school students in many respects such as cognitive, emotional, psychological and physical. It is aimed to examine the relationship between cognitive flexibility levels and cognitive emotion regulation strategies of high school students who were exposed to peer bullying. Furthermore, it is examined whether these variables differ according to sociodemographic differences. Methods: The sample of the study consists of 400 high school students reached via the internet from different cities of Turkey in 2020. The data in the study were obtained using “the peer bullying scale”, “cognitive flexibility scale”, “cognitive emotion regulation scale” and “sociodemographic information form” prepared by the researcher. Results: It was found statistically significant that boys were subjected to more bullying on the peer bullying scale in the subscales of terror, teasing, and open attack. The rates of bullying students in vocational and technical high schools, who had poor school success and friendship relationships, were also found to be statistically significant (p<0.005). Students with good school achievement and friendship relationships had higher levels of cognitive flexibility, while boy students and those with very good friendship relationships scored highly on the “refocusing on planning” subscale of the cognitive emotion regulation scale (p<0.05). Conclusion: According to our research, cognitive flexibility decreases as peer bullying levels increase. The use of maladaptive cognitive emotion regulation strategies also appear to increase.