- Study Objectives: There is deepening understanding of the effects of sleep on emotional information processing. Emotion information processing is a key aspect of social competence, which undergoes important maturational and developmental changes in adolescence; however, most research in this area has focused on adults. Our aim was to test the links between sleep and emotion information processing during early adolescence. Design: Sleep and facial information processing were assessed objectively during 3 assessment waves, separated by 1-year lags. Setting: Data were obtained in natural environments—sleep was assessed in home settings, and facial information processing was assessed at school. Participants: 94 healthy children (53 girls, 41 boys), aged 10 years at Time 1. Interventions: N/A Measurements and Results: Facial information processing was tested under neutral (gender identification) and emotional (emotional expression identification) conditions. Sleep was assessed in home settings using actigraphy for 7 nights at each assessment wave. Waking > 5 min was considered a night awakening. Using multilevel modeling, elevated night awakenings and decreased sleep efficiency significantly predicted poor performance only in the emotional information processing condition (e.g., b = -1.79, SD = 0.52, confidence interval: lower boundary = -2.82, upper boundary = -0.076, t (416.94) = -3.42, P = 0.001). Conclusions: Poor sleep quality is associated with compromised emotional information processing during early adolescence, a sensitive period in socio-emotional development.