ObjectiveEarly adolescence is marked by elevated psychopathology, including disrupted eating attitudes and behaviors. Reward processing is an identified mechanism in portending eating pathology, that is, aberrant reward responsivity may contribute to disrupted reward‐seeking behaviors (e.g., food consuming). This literature has focused on adults or mid‐to‐late adolescents, with little work done on early adolescence. We examined the linkages between reward feedback processing, indexed by event‐related potentials (ERPs), and changes of emerging disordered eating in community‐dwelling early adolescents.MethodAt T1, 115 youths (66 girls, mean/SD age = 11.00/1.16 years) completed an EEG monetary reward Doors task. Youths completed the Eating Disorder Examination‐Questionnaire Short at T1 and ~6 months (T2) and ~12 months (T3) after T1. In the ERP data, we isolated a reward positivity (RewP) and a late positive potential (LPP) via principal component analysis. We applied multilevel modeling to examine whether baseline ERPs interacted with Time in predicting disordered eating and whether these interactions varied by sex.ResultsWe found a significant Time × LPP interaction in girls but not boys. Among girls, only those with a smaller LPP toward the losses (versus wins), which might reflect suboptimal evaluation and regulatory processes in undesired situations, showed increases in disordered eating from T1 to T3.DiscussionWe provided preliminary yet novel evidence concerning the prospective associations between reward processing and changes of disordered eating in early adolescents. Future studies along this line will be critical for understanding the early mechanisms of eating pathology, identifying youths at risk, and developing prevention strategies.