This article is about bullying, a set of comportments involving physical, verbal or psychological attacks, done intentionally or repeatedly, without visible motivation, by one or more attackers against a more fragile individual from a physical and emotional point of view. The research problem that led to this paper was: "How bullying can affect interpersonal relations at school?" The main objective was to analyze how bullying influences interpersonal relations. The specific objectives were: to analyze bullying occurrences at the researched school; to analyze the teachers and students' opinions about the occurrence and practice of bullying; to analyze the teachers and students' reports regarding bullying interference in interpersonal relations inside the school; and to analyze actions taken by the school professionals considering the bullying interference in the interpersonal relations among the students. So, we analyzed the consequences of those attitudes among students, both victims and attackers, through a case study as Yin (2003) suggests. The research was accomplished in a private school in Vitoria da Conquista (Bahia-Brazil) that had, in 2007, 95 matriculate students. This choice was made because, according to some people, there are problems only in public schools. The research procedures were: direct observation, interviews and questionnaires. With the obtained data, it was possible to deduce that pushy practice is present at school, appearing in unusual situations, obstructing interpersonal relations and the involved ones' learning processes.