BACKGROUND: Although maternal hemoglobin levels during pregnancy are commonly associated with perinatal outcomes, their link to childhood neurodevelopment remains uncertain. OBJECTIVE: This study aimed to examine the associations between maternal hemoglobin in early and late pregnancy and the educational attainment of offspring mid-childhood in a high-resource obstetric setting. STUDY DESIGN: Pregnancy data from a prospective birth cohort (Pregnancy Outcome Prediction Study, Cambridge, United Kingdom, 2008-2012, N=3285) were linked to mid-childhood educational outcomes (Department for Education, United Kingdom). Regression models adjusted for maternal, child, and socioeconomic factors were used to determine associations between maternal hemoglobin, pregnancy complications, and offspring educational outcomes (aged 5-7 years). RESULTS: No association was observed between maternal hemoglobin at 12 weeks and the likelihood of either adverse pregnancy outcomes or children meeting expected educational standards between ages 5-7 years. Higher maternal hemoglobin at 28 weeks was associated with an increased risk of small-for-gestational-age infants (adjusted odds ratio, 1.26 [95% confidence interval, 1.11-1.59]; P=.002) and preterm birth (adjusted odds ratio, 1.38 [95% confidence interval, 1.11-1.81]; P=.005). There were no adverse birth outcomes associated with anemia. However, children of mothers who were anemic at 28 weeks had ∼40% increased risk of not attaining expected educational standards at age 5 (adjusted odds ratio, 1.42 [95% confidence interval, 1.03-1.95]; P=.03). There was no association between maternal anemia at 28 weeks and educational performance at ages 6-7. No associations were found between high maternal hemoglobin concentrations (top decile) or change in hemoglobin concentrations between 12 and 28 weeks and childhood educational attainment. CONCLUSION: Maternal anemia at 28 weeks of pregnancy is associated with reduced educational attainment at 5 years old but not at older ages (6-7 years old). A proactive approach to increasing maternal hemoglobin in high-resource settings is unlikely to impact long-term childhood educational attainment.