The work done here involved estimating the extent of bullying in Latin American schools and its impact on the academic achievement of primary school students. Pupils' socio-demographic characteristics were analysed and linked with bullying. Three- and four-multilevel models were applied to data from the Second Regional Comparative and Explanatory Study (SERCE) conducted by the United Nations Educational, Scientific and Cultural Organization (UNESCO), analysing 2,969 schools, 3,903 classrooms and 91,223 sixth-grade students in 16 Latin American countries (not including Mexico for the association between school bullying and academic performance). The study found that bullying is a serious problem throughout the region; students who suffer peer aggression yield a significantly lower performance in reading and math than those who do not; and those in classrooms with more episodes of physical or verbal violence perform worse than those in less violent classroom settings.