Maternal periconceptional diets have known associations with proper offspring neurodevelopment. Mechanisms for such associations include improper energy/nutrient balances between mother and fetus, as well as altered offspring epigenetics during development due to maternal nutrient and inflammatory status. Using a comprehensive food frequency questionnaire and assessing offspring temperament with the Infant-Toddler Social and Emotional Assessment ( = 325, mean age = 13.9 months), we sought to test whether a maternal periconceptional diet characterized by high glycemic loading (MGL) would affect offspring temperament using adjusted ordinal regression. After limiting false discovery to 10%, offspring born to mothers in tertile 3 of glycemic loading (referent = tertile 1) were more likely to be in the next tertile of anxiety [OR (95% CI) = 4.51 (1.88-11.07)] and inhibition-related behaviors [OR (95% CI) = 3.42 (1.49-7.96)]. Male offspring were more likely to exhibit impulsive [OR (95% CI) = 5.55 (1.76-18.33)], anxiety [OR (95% CI) = 4.41 (1.33-15.30)], sleep dysregulation [OR (95% CI) = 4.14 (1.34-13.16)], empathy [6.68 (1.95-24.40)], and maladaptive behaviors [OR (95% CI) = 9.86 (2.81-37.18)], while females were more likely to exhibit increased anxiety-related behaviors [OR (95% CI) = 15.02 (3.14-84.27)]. These associations persisted when concurrently modeled with the maternal-Mediterranean dietary pattern. In a subset ( = 142), we also found MGL associated with increased mean methylation of the imprint control region of . In conclusion, these findings highlight the importance of maternal dietary patterns on offspring neurodevelopment, offering avenues for prevention options for mothers.