This research shows the main results of questionnaire research of student harassment experiences of 1,237 female and male high school students in the Czech Republic by their teachers. Harassment can demonstrate itself in a wide variety of behaviors, which teachers perform to strengthen their dominance over students in order to achieve a professional and/or personal advantage. In the presented research the main focus was on gender motivated and sexual behaviors, in wider context, the crossing of borders of a professional pedagological relation between teacher and student. The results indicate that nearly 2/3 of research participants have had some experience with various types of inappropriate teacher´s behaviour including unjust treatment and the application of gender stereotypes. Experiences with unwanted sexual attention were not as common and the least mentioned (but still suprisingly high) was the occurance of sexual coercion.