Adolescence is not only a critical period for depression onset, but also the period that gender became a risk factor for depression susceptibility (). Puberty is one of the most important landmarks of adolescence with clear consequences in emotion regulation, thinking and behavior. During puberty, steroid hormones trigger various brain circuits remodeling responses for functional and structural changes (). The serotonin transporter gene promoter polymorphism (5HTTLPR) has been implicated as a moderator of the effects of psychosocial stressors in depression in several studies (). Furthermore, there is clinical () and animal () evidence for age-related developmental moderation of serotonergic pathways. The aim of this study was to test whether the 5HTTLPR polymorphism would be associated with depressive symptoms in adolescents in different stages of development. We hypothesized that low functional variants would be associated with higher depressive symptoms only in post-pubertal adolescents.