We examine the effects of the gender of the victim and offender and their relationship to each other on whether sexual and physical assaults are reported to the police. We also examine the reasons victims give for not reporting assaults and whether reporting patterns have changed over time. The analyses are based on a sample of 6,291 physical assaults and 1,787 sexual assaults from the National Violence Against Women Survey. The results suggest that victims are just as likely to report domestic assaults as they are to report assaults by other people they know. Male victims are particularly reluctant to report assaults by their intimate partners, whereas third parties are particularly unlikely to report assaults by partners of either gender. Sexual assaults, particularly those that involve acquaintances, are less likely to be reported. These patterns have not changed since the 1960s.