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RATIONALE Sleep duration is critical to growth, learning, and immune function development in infancy. Strategies to ensure that national recommendations for sleep duration in infants are met require knowledge of perinatal factors that affect infant sleep. OBJECTIVES To investigate the mechanistic pathways linking maternal education and infant sleep. METHODS An observational study was conducted on 619 infants whose mothers were enrolled at the Edmonton site of the CHILD birth cohort. Infant sleep duration at three months was assessed using the Brief Infant Sleep Questionnaire. Maternal education was collected via maternal report. Prenatal and postnatal depression scores were obtained from the 20-item Center for Epidemiologic Studies Depression Scale (CES-D). Birth records and maternal report were the source of covariate measures. Mediation analysis (PROCESS v3.0) was used to examine the indirect effects of maternal education on infant sleep duration mediated through prenatal depression and birth mode. MEASUREMENTS AND MAIN RESULTS At three months of age, infants slept on average 14.1 h. Lower maternal education and prenatal depression were associated with significantly shorter infant sleep duration. Emergency cesarean section birth was associated with 1-hour shorter sleep duration at three months compared to vaginal birth [without intrapartum antibiotic prophylaxis] (β: -0.99 h; 95% CI: -1.51, -0.48). Thirty percent of the effect of lower maternal education on infant total sleep duration was mediated sequentially through prenatal depression and birth mode (Total Indirect Effects: -0.12, 95% CI: -0.22, -0.03, p < 0.05). CONCLUSIONS Prenatal depression and birth mode sequentially mediate the effect of maternal education on infant sleep duration.