The purpose of the present study was to investigate associations of dietary intake including vitamin D, folate, and n-3 and n-6 polyunsaturated fatty acids (PUFA) in pregnant women with broad autism phenotype (BAP). The Japan Environment and Children's Study is a government-funded birth cohort study. All complete data of 92,011 were analyzed. The Japanese version of the Autism Spectrum Quotient was used to assess mothers' BAP level, and a food frequency questionnaire was used to estimate their dietary intake. Mothers with BAP consumed less vegetables, fruits, and fish and shellfish, and they consumed lower folate, vitamin C, vitamin D, and n-3 PUFA than their counterparts. Dietary intervention should be considered for pregnant women with high BAP scores.