In Australia, the increase of reports of acquaintance sexual assault has not been met by a proportionate increase in the conviction rates of such cases. As juries of lay people are responsible for convicting perpetrators of such cases, this thesis investigated the factors that influence case relevant perceptions. Distinctiveness was predicted to affect attributions of the perpetrator’s behaviour, such that internal attribution would be higher and external attribution would be lower if the perpetrator had engaged in similar behaviour toward others. Distinctiveness was further expected to affect case relevant perceptions, such that low distinctiveness information would lead to lower victim blame, and higher ratings of perpetrator guilt likelihood, blame and fault. This effect was predicted to be qualified by a distinctiveness by perpetrator gender interaction, such that the effect would be greater for female perpetrators. It was predicted that internal attribution would mediate the relationship between distinctiveness and case relevant perceptions. A total of 274 firstyear psychology students from the University of Queensland read a scenario in which offense type (sexual assault vs. sexual harassment), perpetrator gender (male vs. female) and distinctiveness (high vs. low) were manipulated. They then rated their agreement on measures of case relevant perceptions. As expected, distinctiveness information led to higher ratings of internal attribution; however there was not direct effect of distinctiveness on case relevant perceptions. However, distinctiveness information indirectly affected case relevant perceptions, via internal attribution. Contrary to expectations, there was also no distinctiveness by perpetrator gender interaction on case relevant perceptions. Explanations for the findings and their theoretical and practical implications are discussed, in addition to suggestions for future research.