Black American adolescent girls constitute approximately one third of the US youth legal system population. Their overrepresentation in the youth punishment system is an indicator of significant physical, sexual, and/or behavioral health needs. Since less is known about perceptions of HIV/STI risk among Black girls with juvenile justice histories, we used intersectionality theory to explore the following: (1) how a sample of Black girls in detention endorse their perceptions of sexual safety given the multiple intersections of their race, gender, and SES and (2) how their endorsements align with interlocking systems of social inequality for system-involved Black at the social structural level. We examined relational and behavioral factors associated perceived HIV/STI risk. Among a sample of 188 Black girls (ages 13–17 years), we examined parent and partner sexual communication, fear of condom negotiation, a positive STI test, and partner risk profile as significant correlates. Major findings indicated that greater partner communication was associated with higher perceived HIV/STI risk, whereas having had a risky sexual partner, fear of condom negotiation, and having had a positive STI test were correlated with lower perceived risk. The significant factors identified in this study can be the focus of STI prevention and intervention programs for Black girls with youth punishment histories.