Major depressive disorder in adolescents is an important public health concern. It is common, a risk factor for suicide and is associated with adverse psychosocial consequences. The UK National Institute for Health and Care Excellence guidelines recommend that children and young people with moderate-to-severe depression should be seen within Child and Adolescent Mental Health Services and receive specific psychological interventions, possibly in combination with antidepressant medication. Cognitive behavioural therapy (in some studies) and interpersonal psychotherapy have been demonstrated to be more effective than active control treatments for depressed adolescents. For children with depression, there is some evidence that family focused approaches are more effective than individual therapy. Fluoxetine is the antidepressant with the greatest evidence for effectiveness compared with placebo. Treatment with antidepressants and/or psychological therapy is likely to reduce suicidality, although in some young people, selective serotonin reuptake inhibitors lead to increased suicidality. There is limited evidence that combination of specific psychological therapy and antidepressant medication is better than treatment with monotherapy. There are methodological limitations in the published literature that make it difficult to relate study findings to the more severely ill clinical population in Child and Adolescent Mental Health Services. Young people should have access to both evidence-based psychological interventions and antidepressants for paediatric depression. Collaborative decisions on treatment should be made jointly by young people, their carers and clinicians, taking into account individual circumstances and potential benefits, risks and availability of treatment.