Juvenile drug courts (JDCs) are a growing response to adolescent substance use, but better understanding of modifiable risk factors is needed to improve JDC outcomes. JDCs also serve dual public health and justice functions, heightening potential impact on co-occurring health factors like risky sex. However, mental health symptoms and peers’ activities may impede JDC effectiveness. In a unique longitudinal sample of 105 adolescents involved in JDCs, we find elevated internalizing symptoms and deviant peer behavior were each associated with increased substance use, with similar effects on risk for condomless sex. Findings inform intervention targets that could maximize JDC programming impact.