Male-on-male sexual assaults challenge prevention and response personnel, law enforcement, and the military justice system. Before this study, limited research on military sex offender populations and none specifically on military male-on-male offenders was conducted. In this exploratory study, 171 cases of penetrative male-on-male sexual assaults were examined using criminal investigation files provided by the United States Army. The results yielded a more salient picture of offender and victim dynamics, the criminal and predatory behaviors of the offender, the levels of violence used in these assaults, a better understanding of male victim behaviors, and gave insight into the cognitive distortions used by the offenders which can assist law enforcement with proper investigation and interviewing techniques. Results found that victims were those in the offender's direct unit and assaults frequently occurred as the victim was asleep, unconscious, or incapacitated through ingesting drugs or alcohol. Offenders performed various acts with their victims through the course of the assault, with offender to victim fellatio or offender to victim fellatio in addition to anal penetration, being the most common. This was an important distinction in military sexual assaults, as offender behavior could be seen as an extension of potential fantasy enactment as motivation for the assault resulting in little to no physical resistance and less of a chance of rejection by the victim. Most assaults were nonviolent in nature. This study also provided the foundation for a more comprehensive military offender behavior project currently ongoing.