Changes in sleep patterns among children following traumatic experiences may be indicative of post-traumatic psychiatric disorders and contribute to disease persistence. We evaluated long-term changes in the sleep habits of 1919 junior high school students who experienced the 2011 Japan earthquake and tsunami, and examined the associations among sleep patterns, trauma symptoms, and specific traumatic events. The Post-Traumatic Stress Symptoms for Children-15 items self-completion questionnaire was distributed to the children, and a questionnaire regarding three specific traumatic events (home damage, bereavement, and evacuation) was distributed to their teachers. Compared to the same survey conducted 8 months after the disaster, a 20-month post-disaster survey revealed significantly shorter mean sleep duration and a delay in sleep phase (P < 0.0001). On the 20-month survey, weekday sleep duration was shorter and sleep–wake pattern delayed in children who had experienced home damage compared to children with no such experience (P < 0.01). Children who had experienced bereavement also reported a shorter mean sleep duration on the 20-month survey compared to children reporting no bereavement experience (P < 0.05). Differences in sleep duration between weekdays and holidays at 20 months post-disaster suggested a sleep debt due to sleep disruption. There were no significant differences in Post-Traumatic Stress Symptoms for Children-15 items total scores between groups defined by the type of traumatic experience. Traumatic events (home damage, bereavement) associated with the 2011 Japan earthquake and tsunami have caused long-term sleep disruption in children from this region.