We examined sleep difficulties preceding death in a sample of adolescent suicide completers as compared with a matched sample of community control adolescents. Sleep disturbances were assessed in 140 adolescent suicide victims with a psychological autopsy protocol and in 131 controls with a similar semistructured psychiatric interview. Rates of sleep disturbances were compared between groups. Findings indicate suicide completers had higher rates of overall sleep disturbance, insomnia, and hypersomnia as compared with controls within both the last week and the current affective episode. Group differences in overall sleep disturbance (both within the last week and present episode), insomnia (last week), and hypersomnia (last week) remained significant after controlling for the differential rate of affective disorder between groups. Similarly, overall sleep disturbance (last week and present episode) and insomnia (last week) distinguished completers in analyses accounting for severity of depressive symptoms. Only a small percentage of the sample exhibited changes in sleep symptom severity in the week preceding completed suicide, but of these, a higher proportion were completers. These findings support a significant and temporal relationship between sleep problems and completed suicide in adolescents. Sleep difficulties should therefore be carefully considered in prevention and intervention efforts for adolescents at risk for suicide.