There is scientific evidence on the protective effects of nut intake against cognitive decline in the elderly; however, this effect has been less explored in child neurodevelopment and no studies have explored the potential longitudinal association with nut intake during pregnancy. We aimed to analyze the association of maternal nut intake during pregnancy with child neuropsychological outcomes. We included 2208 mother-child pairs from a population-based birth cohort in four regions of Spain. The follow up settings were during pregnancy (first and third trimesters), birth, 1.5, 5 and 8years. Neuropsychological examinations were based on Bayley Scales of Infant Development (1.5years), McCarthy scales of Children's Abilities (5year), Attention Network Test (ANT, 8year) and N-Back test (8year). Nut intake in pregnancy was reported through a validated food frequency questionnaire during the first and the third trimester. Multivariable regressions analyzed associations after controlling for priori selected confounders notably maternal education, social class, body mass index, energy intake, fish intake, omega-3 supplements, alcohol consumption and smoking habits during pregnancy. Children within the highest tertile of maternal nut consumption during first pregnancy trimester (>32g/week) had a decrease of 13.82ms [95% confidence interval (CI) -23.40, -4.23] in the ANThit reaction time standard error, compared to the first tertile (median 0g/w). A similar protective association pattern was observed with the other cognitive scores at the different child ages. After correcting for multiple testing using Bonferroni familywise error rate (FWER), Hochberg FWER and Simes false discovery rate, ANThit reaction time standard error remained significant. Final model estimates by inverse probability weighting did not change results. Third pregnancy trimester nut intake showed weaker associations. These data indicate that nut intake during early pregnancy is associated with long-term child neuropsychological development. Future cohort studies and randomized clinical trials are needed to confirm this association pattern in order to further extend nutrition guidelines among pregnant women.