Children’s individual experience gained within families may lead to the development of both prosocial and aggressive behaviours. The aim of the paper is to analyse the phenomenon of aggression in the family environment. Extensive specialist literature indicates that there are often many co-occurring factors that determine child aggression. Children live in a dysfunctional family, in conditions of poverty and parental pathology, experience parental hostility and violence, are neglected, their vital biological and psychological needs are not met, they undergo inadequate upbringing training. They also experience aggression in sibling relations. Thus, the family provides them with comprehensive aggressive education for years. An important issue is to prevent and control aggression in the family. It is not easy and requires actions at three levels: social, individual and family. The article also presents an interesting intervention model in a sibling aggression situation.