The thesis discusses the highly topical issue of bullying and cyberbullying among children. It is divided into four chapters. The first chapter of the thesis describes bullying in general. The second and third part of the thesis explains characteristics of cyberbullying, the most frequent occurrence being specifics of the environment, its expansion and forms. There is mentioned the possibility of prevention and ways of dealing with the incidence of cyberbullying. The theoretical part is compiled on the basis of specialized literature by Czech and foreign authors. The content of the fourth chapter focuses on the methodical investigation at selected schools. The aim of the study was to determine whether and to what extent students attending individual schools encounter cyberbullying.