The psychometric properties of an adolescent mental health outcome instrument (Youth Outcome Questionnaire Self-Report version [Y-OQ-SR]) were examined. Participants were 206 adolescents (ages 12-18; mean age=15). The Y-OQ-SR was evaluated in terms of its internal consistency, test-retest reliability, and concurrent validity. Criterion measures included the Behavior Assessment System for Children, Self-Report of Personality-Adolescent Version (SRP), and the Child Behavior Checklist Youth Self Report (YSR). Analyses revealed very good internal consistency and test-retest reliability of the Y-OQ-SR total score and subscales, and moderate to good concurrent validity with the SRP and YSR. The Y-OQ-SR appears to be a valid and reliable self-report measure of psychosocial distress that warrants further study in youth psychotherapy research.