What accounts for the puzzling persistence of sexual assault of both women and men within the ranks of the US military? Despite increasing efforts to end this intraforce violence, sexual assault of women persists at levels comparable to those in the civilian population and significantly higher than that of other crimes (data challenges prevent comparing rates for men). Drawing on recent analysis of rape as a practice rather than a strategy of war, we suggest the answer lies in the socialization not only of recruits but also of officers. We draw on an original typology of socialization processes and analysis of four well-documented cases to suggest the following account of why sexual assault persists. First, informal socialization processes (including sexualized hazing) trivialize sexual harassment and assault, establish assault as an appropriate form of punishment (including of those transgressing military gender norms), and license retaliation against victims who report. Second, officers sometimes sexually harass and assault subordinates, thereby endorsing similar acts by servicemembers under their command. Third, formal socialization processes of enlisted men and women, despite recent reforms, continue to reproduce a masculinity that undermines policies that seek to prevent sexual assault, in part because it fails to override these unauthorized and illegal socialization processes. Finally, the socialization of officers, combined with problematic incentive structures, undercuts efforts to end the de facto tolerance of sexual abuse by many officers. In our emphasis on horizontal as well as top-down socialization processes, and on those that subvert official policies as well as those that seek to inculcate them, we also contribute to scholarly understanding of socialization within organizations more generally.