With regard to research work in the field of sexual offences, the validity of police crime statistics is restricted as the dimensions of unreported crime are suspected to be enormous. Therefore, we conducted empirical research with students at Erfurt University of Applied Sciences using an online survey in order to investigate quantities and manifestations of sexual victimisation as well as motivations for and against reporting offences like sexual assault and rape. As none of the victims made a complaint, all criminally relevant sexual offences (8.7 %, n = 46) can be assigned as unreported cases. Although affected persons described diverse and individual reasons against reporting a crime, three main motivations could be identified by using factor analysis. These were: fear of secondary victimisation, apprehensions regarding the criminal proceeding and emotional distress as well as a lack of confidence in the judicial system. Because of these concerns, victims of sexual assault and rape do not support the idea that professional consultants are obliged to report crimes. Furthermore, we observed a correlation that sexually victimised persons are more afraid of both general and specific crime. This particularly applies to the cognitive component of specific fear of crime.