The aim of this research was to examine changes in the frequency of victimization, aggressive behavior and positive behavior among children after participating in the program “Child Friendly Communities”. 302 children between 9 and 15 years of age participated; the children, who at the time of the intervention were completing the fifth and sixth grades of basic education in two public schools with high levels of marginalization, in the metropolitan area of Guadalajara (Mexico), were evaluated using Orpinas’ (2009) scales of victimization, aggression and positive behaviors. We observed changes in their perception of the violence performed against them and a growing recognition of the aggression exercised by them against peers in those children who prior to the intervention reported not being aggressive or who obtained a low score on levels of aggression. Likewise, children who tend to be aggressors showed a significant decrease in aggression exerted against others, both direct and relational. Results suggest that the program Child Friendly Communities helps to decrease the normalization of violence against children as well as the aggressive behavior against peers.