Background: Vitamin D deficiency in expectant mothers is very common in India. As a consequence, the possibility of hypoplasia of teeth and resultant propensity for faster progression of early childhood caries (ECC) is expected to be higher in Indian children. Aim: This study aimed to determine the relationship between prenatal vitamin D intake of mothers and dental caries experience in their preschool children, and whether vitamin D deficiency in mothers could be a risk factor for tooth decay in their children. Design: This cross-sectional study included 120 mothers of children aged up to 71 months with dental caries attending the Department of Pediatric Dentistry in India. Mothers were surveyed about their prenatal vitamin D intake and their practices regarding vitamin D and sunlight exposure. Children were clinically examined, and their caries status was recorded using the decayed, extracted, filled teeth (deft) index. Results: Data were analyzed descriptively and correlated using an independent t-test. Binary logistic regression was employed to predict the effects of the duration of sun exposure and vitamin D deficiency on dental decay. The correlation of mothers’ prenatal vitamin D intake was significantly associated weekly with children's caries experience. Their sun exposure (p = 0.002) and practices adopted (p = 0.0001) regarding vitamin D levels were statistically significant for children's caries status. Improper brushing frequency was also significantly associated with higher deft scores. Conclusion: The association between mothers’ prenatal vitamin D intake and health practices related to vitamin D with dental caries was not confirmed. Subjects with vitamin D deficiency and their children had significantly higher odds of developing dental decay. However, our findings suggest that 25-hydroxyvitamin D insufficiency may be a risk factor for developing dental caries in children.