Youth perinatally HIV infected (PHIV) or HIV exposed, but uninfected (PHEU), are aging into adolescence and adulthood with multiple complex risk factors for mental health (MH) problems and poor MH treatment utilization. Our aims were to estimate prevalence of MH diagnoses, clinically significant symptoms, and MH treatment utilization among youth with PHIV and among PHEU youth, 10-22 years old. We also aimed to identify correlates of diagnoses and treatment utilization. Analyses of data from standardized interviews, behavioral assessments, and chart review of 551 youth revealed that 36% had a previous or current MH diagnosis, with no significant HIV status group differences. Prevalence of clinically significant symptoms was 15% for both groups, of whom a third had no diagnosis, and half were not receiving treatment. Among youth with a current MH diagnosis, those with PHIV had greater utilization of services than PHEU youth (67% vs. 51%; p = 0.04). Factors associated with MH diagnoses and/or treatment utilization included caregiver characteristics, age and sex of child, HIV status, and stressful life events. Prevalence of MH diagnoses was higher than in the general population, but lower than in similar perinatally HIV-exposed cohorts, with some unmet service needs, particularly in PHEU youth. Family characteristics warrant careful consideration in early diagnosis and treatment of MH problems among youth affected by HIV.