Bullying in Adolescents: Differences between Gender and School Year and Relationship with Academic Performance

School bullying is a phenomenon of unjustified aggression in the school environment that is widespread throughout the world and with serious consequences for both the bully and the bullied. The objectives of this research were to analyze the differences between the different bullying categories by gender and academic year in primary and secondary education students, as well as their relationship with academic performance. To categorize students according to their bullying experiences, the European Bullying Intervention Project (EBIPQ) Questionnaire was used. The Chi-square test was used to compare the scores obtained by the students in the EBIPQ based on gender and academic year, and the one-way ANOVA test was used to analyze its relationship with academic performance. Research participants were 562 students from the 5th (n = 228) and 6th (n = 186) primary school years and the 1st (n = 134) and 2nd (n = 94) secondary school years. They were males (50.5%) and females (49.5%) ranging in ages from 10 to 15 years old (mean = 11.66, standard deviation = 1.206). The results showed statistically significant differences in gender and academic year, indicating a greater number of boys in the role of the bully/victim and girls in that of non-bully/non-victim. The most aggressive students were in the 2nd year of ESO (12–13 years old). Regarding academic performance, statistically significant differences were obtained that confirm the hypothesis that performance or average grade varies according to the category of bullying in which students find themselves. The academic performance of the non-bully/non-victim and those in the victim category was found to be higher than that of bullies and bully/victim students.