The objective of this study was to explore prison-based behavioral characteristics and personal/descriptive characteristics of the different groups involved in bullying behavior, with an additional goal of exploring gender differences regarding these characteristics. The study consisted of 406 prisoners from 4 separate adult prisons, 196 were female and 210 were male. Prisoners were placed in one of four groups (pure bullies, bully/victims, pure victims, or not-involved) based on a self-report behavior checklist. Results showed prison-based behaviors by prisoners appeared to be more predictive of group membership than the personal/descriptive characteristics such as age, sentence length, offense, and institutional history addressed in this present study. Both victim groups showed the most drug-related behavior and negative behavior towards staff. Gender differences were found with negative behavior more predictive of group membership for female bully victims, whereas for male bully victims, drug-related and proactive/positive behaviors were more predictive of group membership. In summation, the study showed how the personal/descriptive characteristics that adult prisoners brought with them to the prison environment appeared to be less important in predicting group membership than behaviors they displayed within the prison. These research findings offer assistance in developing bullying intervention programs and direction for future research. Tables and references