BACKGROUND: Over the past two decades new and key randomized controlled trials have reported the efficacy, clinical and cost effectiveness of psychological and pharmacological treatments for adolescents with major depression. METHODS: The literature was searched through pubmed, psychinfo, scopus and web of science for randomized controlled trials of current major depression together with meta-analyses and systematic reviews of trials between 2000 and 2017. Those specific to the adolescent years (11-18 years) were taken as the primary source for this narrative review. Additional selected studies in adults were used to illustrate methodological issues. RESULTS: Manualized psychological therapies and the SSRI fluoxetine are more effective than active placebo in the treatment of major depressions. Mild to moderate illnesses attending community-based services are likely to benefit from psychological treatment alone. Moderately to severely ill patients attending clinic and hospital services are likely to benefit from monotherapies or combining psychological and pharmacological treatment. Antidepressants carry a small but significant side-effect risk including increased suicidality. Side effects from psychotherapies are somewhat lower but specific negative consequences remain less well characterized. There is some evidence that CBT-based approaches prevent onset of major depression episode in well adolescents at high-risk. Other psychological interventions have not been adequately studied. There has been only limited identification of treatment moderators and no clear understanding of therapeutic mechanisms. CONCLUSIONS: There is now a range of clinically effective treatments for depressed adolescents. Future research needs to reveal moderators of and mechanisms for individual differences to treatment response, determine psychotherapies of value for milder depressions, enhance our understanding of safety and side-effects for all treatments, and consider how to reduce and treat treatment-resistant cases.