Persons living with human immunodeficiency virus (HIV)/AIDS have a substantial burden of co-occurring substance use disorders (SUDs); untreated alcohol and drug use disorders among people living with HIV/AIDS contribute to worse HIV care outcomes. SUDs are associated with key health behaviors and outcomes, including delays in seeking medical care, poor engagement in treatment, reduced adherence to medical treatment and antiretroviral therapy, immunosuppression, increased HIV transmission through risky sexual behaviors, and increased burdens on health care systems. HIV infection comorbid with SUD and a psychiatric disorder is a clinically challenging condition creating a complex set of medical and psychosocial challenges.