Abstract Many studies have examined the impact of single nutrients on neural tube defect (NTD) risk, particularly folate. The impact of dietary patterns or nutrients in combination has received much less attention. This study examines the association of diet quality with NTD risk, using food frequency data from a population-based case–control study of NTDs ( n=454 cases and 462 controls). The diet quality score was based on low (<10th percentile among controls) versus high (>90th percentile) values for intakes of iron, vitamins B 6 and A, calcium, folate, and percentage of kilocalories from fat and from sweets (range=0–14). Women with a low score (i.e., <4, or <10th percentile) had an elevated risk of an NTD-affected pregnancy (odds ratio 1.6, 95% CI 1.0–2.6). Stratified analyses suggested that the effect may be restricted to certain groups of women who may be at greater nutritional risk (i.e., women who did not take vitamin supplements or regularly consume breakfast cereals before pregnancy).