Approximately 80% of all arrested youth are diverted from detention and supervised in the community through probation, specialty courts and other community-based diversion efforts. Justice-involved youth have greater psychiatric impairment, substance use and sexual risk behaviors than their non-justice-involved peers. Family-based interventions to address mental health, substance use and recidivism have been successful in improving these youth outcomes; but the lack of integration of HIV/STI prevention is notable given the co-occurrence of substance use, delinquency and sexual risk-taking behaviors among justice-involved youth. Moreover, emotion dysregulation may be an important and understudied underlying construct of these co-occurring risk behaviors for justice-involved youth. Study participants were 47 caregiver-youth dyads enrolled in a juvenile drug court program. As part of a pilot efficacy trial, dyads were randomized to a 5-session family-based integrated substance use and HIV/STI prevention intervention that relied on affect management strategies for risk reduction or an adolescent-only psychoeducation condition matched for time and attention. Data collected at baseline and 3 months post-intervention suggest that a family-based integrated affect management substance use and HIV prevention pilot intervention may lead to justice-involved youths’ enhanced motivation to change their marijuana use, decreased marijuana use and decreased risky sexual behavior over time. Future research is required to replicate these pilot trial findings and should also examine family-level mediators and moderators of treatment response, particularly with respect to HIV prevention efforts for these youth.