The article presents results of a research, which primarily aimed to look closer at the changes in forms, scale and increase of aggressive behaviours of students at all the different learning and upbringing stages. For primary school the most characteristic behaviours are verbal aggression (31,1% of students admit to behave that way), physical aggression but to a lesser degree (13,7%), aggression against teachers (11,6%) aggression against objects (8,8%). Other forms of aggression occur less often, they are admitted by 2,6% to 5,1% of students. In the lower secondary schools we can observe a higher figure of students using also other forms of aggression. Still the dominant form of aggression is the verbal one (38,1%), auto-aggression appears more strongly in form of alcohol abuse and abuse of other psychoactive substances (19,9%), aggression against teacher has a higher level too (19%), as well as against objects (17,2%), physical abuse (12,7%). Psychological abuse, together with family disobedience, occurs more often than in primary schools.