Bullying carries great harm for all involved, undermining academic achievement as well. The strength of such impact is yet to be clarified, existing many possibilities and variables to analyze -- classroom behavior being one. The present cross-sectional investigation goal was to study the impact of bullying (mediated by the classroom behavior) on the academic achievement. Participants consisted of 288 children (from the 1st to 4th school years), 51% females and 49% males, and an average age of: M= 8.09 years (SD = 1.193; Min = 7.94, Max = 8.21). Children filled out a self-report questionnaire on bullying; their teachers reported on classroom behaviors and academic achievement. Results showed that the bullying situation itself, didn't significantly explain the academic achievement of those involved. Indirect effects were found for both victims and perpetrators. Victims revealed worse school results through worse classroom behavior (specifically, excessive motor activity). Aggressor presented worse school results through worse classroom behavior (specifically, opposition behavior, excessive motor activity, and hyperactivity). These results highlight the importance of the educational agents' attention to the existing behaviors in their classrooms, not only to the disruption established in each classroom's environment, but as a possible sign of an involvement in the existing bullying dynamics.