The present study examined the behavioural differences in sexual assault offences in relation to the offender-victim relationship (stranger versus non-stranger). These differences were examined specifically in the context of four interpersol themes of interaction: domince, submission, hostility and cooperation. The details of 100 sexual offence cases (50 stranger and 50 non-stranger) were content-alysed, generating 58 dichotomous variables, covering offender and victim behaviour during the offence. ?2 tests comparing the two samples found that offenders who were strangers to their victims were more likely than non-stranger offenders to display behaviours that indicate a hostile, violent offence style. In contrast, those offenders who knew their victims were more likely than strangers to display a less violent and more persol, compliance-gaining offence style. These findings are discussed in terms of their implications for offender rehabilitation and victim support.