Results indicated that prison violence, although still mainly an individual level event, was exacerbated in specific prison contexts; data collected from 30 prisons revealed that age and aggression were the most robust predictors of inmate-on-inmate assaults in terms of multilevel effects. Aggressive inmates were found to commit more assaults in prisons that were crowded and had greater percentage of younger inmates (under 25). The significant results for age and aggression on the full contextual model indicate continued support for the individual level importation theory as a strong predictor of inmate-on-inmate assault. Furthermore, the importance of the aggression variable indicates that inmate-on-inmate assault is still predominantly very personal and psychological in nature. Most studies on inmate assaultive behavior consider only one level of analysis, thereby ignoring the importance of prison context in inmate behavior; this study extended past research by combining inmate and prison level data into a multilevel model in order to explain inmate-on-inmate, non-deadly assaults. Policy implications and suggestions for multilevel theory prison violence are discussed. Information on inmates came from surveys administered to 1,054 inmates in 30 prisons: 11 in Kentucky, 11 in Ohio, and 8 in Tennessee. Self-report data collection was chosen because the use of official prison records has been shown to be problematic due to the fact that large amounts of prison violence often go unnoticed or unreported by prison staff. Limitations and suggestions for future research are detailed. Tables, notes, references