Objective: Post-traumatic stress symptoms (PTSS) in out-of-school youths (OSYs) may be influenced by alcohol use, but there is a lack of evidence explaining how PTSS affect alcohol use problems in OSYs. The present study aimed to investigate the relationships among PTSS, quality of life, and alcohol use in OSYs. Methods: In total, 125 OSYs (46.4% male) in South Korea completed the Korean Version of the Child Report of Post-Traumatic Symptoms (CROPS), the KIDSCREEN-27 Quality of Life Measure for Children and Adolescents, and the Alcohol Use Disorders Identification Test-Consumption. Results: Mean CROPS score was 18.7 (SD=11.6); 37.6% were problem drinkers. Quality of life in the domain of parent relations and autonomy significantly mediated the relationship between PTSS and alcohol use problems. OSYs with high parental satisfaction and autonomy were less likely to have alcohol use problems even with PTSS. Conclusion: Family assessments and therapeutic approaches are needed for OSYs with both PTSS and alcohol use problems.