Aim: to compare three groups of 30 youth (G1 = prosocial behavoir; G2 = observers of bullying; G3 = aggressors in bullying) of both sexes, high school students from a school located in Usme, aged between 12 and 15, with respect to socio-demographic factors (sex and age), psychological factors (masculinity / femininity) and social factors (family functioning and type of relationship established with pairs). Method: descriptive study of comparative type, where the Scale of Prosocial Skills in Adolescents, the IMAFE Masculinity/Femininity Questionnaire, the APGAR Family Questionnaire and a relationship-with-pairs record tab were applied. Results: there is evidence of differences by sex; additionally, no significant differences between the groups in prosocial behavior in parents, or in the family support perceived, nor in the quality of the family communication were found. Conclusion: gender is a variable associated with issuing a prosocial conduct and being aggressors or observers in situations of harassment school.