Objective: Suicide is the second leading cause of death in adolescence. Genetic studies implicate the genetic component of suicide independent from associated psychiatric disorder. Although genetics is an important factor that might be associated with suicide, limited progress is achieved to identify the candidate genes in adolescents. Methods: The study included 97 patients and 106 controls. Five leptin receptor single nucleotide polymorphism (SNP) region examined. Depressive scores were measured with Children Depression Inventory and suicidal behaviour was measured by Suicide Probability Scale. Logistic and linear regression analysis used for determining to predictors. Results: In linear regression analysis (R-2: 0.786) both previous suicide attempt (B:5.553, t:2.613 p: .035) and having a mutant allele in rs1171276 SNP region (B:4.346 t:2.220 p: .048) have been associated with suicidal behaviour. In logistic regression analysis, family history of depression (p < .0001, OR: 4.2 [1.7-9.6]) and number of stressful life events (p: .001, OR: 1.7 [1.3-2.1]) predicted depression significantly. Conclusion: Leptin receptor polymorphism could result in an increase in impulsive behaviour and suicide scores with leptin resistance. Our research is the first study to investigate the relationship between depression, suicidal behaviour and leptin receptor polymorphism in adolescent sample. Similar studies could be carried out on a community basis.