Objetives. To assess the levels of direct and indirect aggression and prosocial behaviors among schoolchildren at public schools located in 13 municipalities of an intermediate region of Colombia. Materials and Methods. A total of 2,785 children aged 3–11 years were assessed using an instrument validated for the Colombian population that measures aggression and prosocial behavior via direct observations of schoolteachers. Results. Boys predominantly exhibited behaviors associated with direct aggression (22.4%), whereas girls exhibited behaviors of indirect aggression (8.0%). Prosocial behaviors were more common in women (67.2%) and in 10-11-year-old children (67.4%). Conclusions. The degree of aggressive behavior may be related to the sociocultural milieu in which children live, and can be detected and subjected to intervention by schoolteachers.