The primary purpose of the present study was to examine whether knowledge of the motivation of an offender can influence participant perceptions of victim and perpetrator responsibility for a sexual assault. In addition, the synergistic influence of victim gender and participant gender with offender motivation was explored. Participants were 171 men and women from a small Northeastern college exposed to a stimulus in which a rapist's motivation was varied as either sexual or violent. Participants were more certain that the stimulus described a rape, recommended a longer prison sentence for the offender, and assigned less blame to the victim when exposed to an offender motivated by violence as opposed to an offender motivated by sex. Offender motivation also interacted with participant gender and victim gender on participants' perceptions of victim blame and offender responsibility. The results suggest that an offender's motivation for rape can influence perceptions of the offender's and victim's responsibility for the assault.