A significant number of adolescents have been exposed to traumatic life events. However, knowledge about the specific sleep disturbance that occurs in individuals after trauma exposure is predominantly based on studies of adults. This study reports specific sleep disturbance in 42 survivors of the 2011 mass shooting at a youth summer camp on the Norwegian island Utøya, mean age = 20.91 years, SD = 2.32, 62.5% females. When compared with matched controls, significantly more survivors reported having sleep disturbances, 52.4% versus 13.6%, d = 0.93, of which onset began at the time of the shooting, ?2 = 14.9, p 1.7, ps = .044 to .028. These results corroborate the effects of a life threat on the range and extent of sleep disturbances, and emphasize the need to better assess and treat sleep disorders in adolescents exposed to trauma.