This study analyzed how the relationships of adolescent students with their peers, the educational community, and their families, as well as their attitudes to school violence, influences becoming a relational bullying victim, a bystander, or an aggressor in a sample of 4,273 Spanish high school students, using Structural Equation Modeling. We applied multi-group analysis, separating girls (n = 2,022) from boys (n = 2,038). The results show that positive relationships serve as a protective factor against participation in situations of aggression and exert a significant influence on the acquisition of transformative attitudes toward violence. Such attitudes, in turn, significantly help prevent bullying. Slight differences were found between boys and girls: mainly in terms of the influence of relationships at school on attitudes toward violence, and the influence of attitudes toward violence on becoming a bullying aggressor, both scoring higher in girls.