In this study, we assess substance use screening and treatment, overall health care use, exposure to prevention messages, and other factors for Medicaid-enrolled adolescents, focusing on those with unhealthy opioid use. Among Medicaid-enrolled adolescents with opioid use disorder (OUD) or risky opioid use who had one or more health care visits in the past year, only about two-thirds received any substance use screening in the past year, although multiple visits were common among these groups. Older youth (ages 16–19) and girls were screened for substance use more often than younger youth (ages 12–15) and boys. Treatment rates were low for youth with risky opioid use (5.1 percent) and OUD (18.1 percent). More than one-quarter of youth with unhealthy opioid use and a third of youth with OUD received mental health care, a critical health care contact that could be leveraged to access effective substance use care. Our results demonstrate that these youth interact with health professionals at high rates but receive very little substance use care, and this is especially true for girls with unhealthy opioid use. Changes in Medicaid policy are needed to increase access to comprehensive, effective care addressing various health care needs, including substance use and co-occurring mental health conditions.