Using in-depth interviews with 20 probation youth (60% female; 35% white; 30% Hispanic; mean age 15years, range=13–17), their caregivers (100% female; mean age 44years, range=34–71) and 12 female probation officers (100% white; mean age 46years, range=34–57), we explored how family and probation systems exacerbate or mitigate sexual risk. We conducted thematic analyses of interviews, comparing narratives of families of sexually risky (n=9) versus non-sexually risky (n=11) youth. Family functioning differed by youth sexual risk behavior around quality of relationships, communication, and limit-setting and monitoring. The involvement of families of sexually risky youth in probation positively influenced family functioning. Data suggest these families are amenable to intervention and may benefit from family-based HIV/STI interventions delivered in tandem with probation.