STUDY OBJECTIVESProsocial behaviors in early childhood predicts future mental health and academic achievements, and its development relies on socio-emotional cognition, such as capacity of cognitive empathy. Vital for early brain development, several studies have revealed the relations between early childhood sleep and prosocial behaviors, while the underlying mechanism remains unexplored. The current study aims to investigate the sleep-prosocial association in a large preschool population, and examined the mediative role of cognitive empathy.METHODSIn this population-based study, a representative sample of 23,524 preschoolers (Mage = 4.29 ± 0.29 years, 48.8 % girls) were recruited in the Shanghai Children's Health, Education and Lifestyle Evaluation-Preschool (SCHEDULE-P) study. Caregivers reported on children's sleep, prosocial behaviors, and cognitive empathy via the Children's Sleep Habits Questionnaire (CSHQ), the Strengths and Difficulties Questionnaire (SDQ), and the Griffith Empathy Measure (GEM), respectively. Logistic regression and mediation model were applied to analyze the sleep-prosocial associations and mediative role of cognitive empathy.RESULTSThe prevalence of prosocial problems was 11.3 % based on parental reports. The mean nighttime sleep duration (NSD) was 9.7 ± 0.7 h. And the prevalence of general sleep disturbances (CSHQ > 48) was 28.2 %. Shorter NSD (aOR = 0.88, p < 0.001) and more general sleep disturbances (aOR = 1.27, p < 0.001) were associated with higher odds of prosocial behavior problems, and the association was robust in most specific sleep problems. Cognitive empathy partially mediated the associations between both NSD (effect = 32.97 %) and general sleep disturbances (effect = 21.05 %) with prosocial behaviors.CONCLUSIONPromoting sleep health and cognitive empathy development in preschoolers with sleep problems may facilitate cognitive empathy development, thereby enhancing prosocial behaviors.