This article examines the difference in victims' reporting behavior regarding crimes committed by males and by females. The authors expect that victims of female offenders are less likely to report to the police than victims of male offenders because of differences in the victim-offender relationship as well as in the victim's sex. With recent developments in Bayesian statistics, new tools have become available that enable the direct evaluation of researchers' expectations. All cases of robbery with assault from the National Crime Victimization Survey have been investigated (n = 478). Findings reveal that female offenders are underreported compared with male offenders and that this can be explained by the victim characteristics but only in combination with the offender's sex. (Contains 5 tables.)