The transition into adolescence is a critical period that features rapid development of the self and elevated depressive symptoms. Maladaptive self-referential processing is an identified cognitive risk factor that predicts the development of depression; elevated depressive symptoms may also reinforce maladaptive patterns of self-referential processing. However, longitudinal data that speak to the directional associations between these two constructs are limited: extant research has focused on simple behavioral measures of self-referential processing, and no work has examined the directional relationships between the neural substrates of self-referential processing and depressive symptoms. In this study, 115 community-dwelling youths (66 girls; Mean age/SD =11.00/1.16 years) completed an EEG version of the Self-Referent Encoding Task (SRET) and reported their depressive symptoms at baseline and approximately a year later. A larger anterior late positive potential (LPP) elicited by negative self-referential processing at T1 predicted higher depressive symptoms a year later, with baseline symptoms controlled for. Further, depressive symptoms at T1 predicted higher drift rate during negative self-referential processing at T2, with baseline drift rate controlled for. We provided novel evidence concerning the bidirectional relationships between self-referential processing and depressive symptoms in early adolescence, with differential patterns observed in different indices of self-referential processing (neural or behavioral).