Using a large sample of students (N=1373; 40% girls; Mage =14 years) from 54 classrooms in South Korea, this study identified subtypes of bullies based on specific combinations of self-reports and peer-reports and examined the intrapersonal and interpersonal factors that explain the differences in characteristics between these identified groups. Latent profile analysis identified four subgroups of bullies: (a) non-bullies (59.5%), (b) peer-identified bullies (21%), (c) self-identified bullies (9.8%), and (d) self/peer-identified bullies (9.7%). Multinomial logistic hierarchical analysis revealed significant differences between the bully subgroups on the four intrapersonal factors (i.e., anti-bullying attitudes, perception of teachers' reaction to bullying, delinquent behavior, and depression; odds ratios [OR] ranged from 0.24 to 3.13) and three of the four interpersonal factors (i.e., overestimated popularity, rejection, and victimization; ORs ranged from 0.39 to 2.26). More specifically, compared to the peer-identified bully group, the non-bully and self/peer-identified bully groups showed opposite patterns of anti-bullying attitudes, delinquent behavior, and peer status (ORs ranged from 0.46 to 3.13). Relative to the peer-identified bully group, the self-identified bully group was more likely to exhibit depressive symptoms and perceive themselves as being victimized, was less likely to endorse anti-bullying attitudes, and had a less positive perception of teacher's reaction to bullying (ORs ranged from 0.24 to 1.40). Gender differences emerged as well. Implications for optimizing the screening of bullying perpetrators and anti-bullying interventions are discussed. [This paper was published in "Journal of School Psychology" v106 Article 101358 2024.]