Earthquake and subsequent relocation adversely affects adolescents' the mental health. Migration may disturb social support system and negatively effects on the well-being of adolescents. We aimed to investigate the long-term effects of relocation, social support following the earthquake on the mental health of adolescents by comparing a control group. This study completed with 434 high school students. Study group compose of 230 adolescents who had survived Van earthquake, (98 adolescents relocated and 132 did not). The control group consisted of 204 adolescents. The data of the study were collected using an information collection form, Child Posttraumatic Stress Disorder (PTSD) - Reaction index, Brief Symptom Inventory (BSI) and Perceived Social Support Scale-Revised. There was a significant difference in the PTSD scores between earthquake and control groups, and also a significant difference in BSI scores between the groups. Participants who had witnessed the death or injury of a family member or friend had significantly higher PTSD scores than others. There were no significant differences in the PTSD and BSI scores between relocated group and not relocated group. In regression analyses, Perceived Family Support was significant predictor of PTSD scores, however neither Perceived Friend Support nor Perceived Teacher Support was found to be a significant predictor. In the long term, the earthquake continues to have a negative effect on adolescents' mental health; however, family support has been found to help adolescents to cope with psychological problems. Strengthening social support systems may play an important role in preventive mental health and psychological rebuilding.