A growing number of studies indicate the ubiquity of school bullying: It is a global concern, regardless of cultural differences. Little previous research has examined whether leading criminological theories can explain bullying, despite the commonality between bullying and delinquency. The current investigation uses longitudinal data on 655 Korean youth, in three schools, to examine the applicability of leading criminological theories (general theory of crime, differential association theory, and general strain theory) in explaining school bullying. Overall, our findings indicate limited support for the generality of these three leading criminological theories in explaining the etiology of bullying. However, the findings show the significant effects of school-generated strains (teachers' physical and emotional punishment and examination related strain) on bullying. Directions for future research and policy implications of these findings are discussed. (Contains 4 tables and 3 notes.)