Tesis para optar al grado de MAGISTER EN ANALISIS ECONOMICO / Bullying is one of the most important social problems faced by students at the school. However, there is scant research in the economic literature about this subject, particularly for developing countries. This paper explores the e ect of being a victim of di erent types of bullying (physical, verbal, social, cyber) on standardized test scores using a unique panel dataset from Chile. Moreover, we are able to see if bullying in uences grade retention rates and college admission tests. Fixed e ect estimates indicates that being bullied decreases student's standardized test score. For instance, being cyber bullied every day decreases math and reading scores in 0.13 and 0.08 S.D respectively. The more frequent bullying is, the more detrimental e ects has on school performance. On top of this, we nd that being bullied increases grade retention probability and decreases college admission test scores. Our results suggests that bullying must be an important matter in policy makers agenda in developing countries, since development is heavily in uence by the cognitive skills acquire at school