The Internet and cyber-space create a platform where a new form has emerged, i.e., bullying, so far occurring mainly within school premises. The study presents results of empirical research conducted at selected elementary and secondary schools in Slovakia in 2017. The aim of the study was to elucidate the most frequent current cyber-bullying platforms and occurrence of individual forms of cyber-bullying with regard to cyber-victims. The research sample consisted of 1004 respondents, aged 10–20 (AM 14.9). Empirical data were collected using the method of questioning in the form of a written questionnaire. We focused on cyber-bullies, electronic platforms and identification of cyber-bullying forms from the point of view of cyber-victims and pupils’ gender and age. It was found out that 24.50% of pupils reported to have been cyber-victimized, girls more often than boys. The most frequent form of cyber-bullying from the point of view of cyber-victims was abusive or offensive language on the Internet and spreading rumours on the Internet.