BackgroundDental caries is one of the most common diseases of childhood. Evidence suggests that malnutrition and vitamin deficiency may increase the risk to dental caries.AimThis study aimed to determine the relationship between vitamin D and dental caries experience in children and whether vitamin D deficiency is a risk factor for tooth decay.Participants and methodsA cross-sectional study was performed on 51 Egyptian children, aged from three to five years and diagnosed from Abo El-Resh Children’s Hospital as ‘Sufficient’, ‘Insufficient’ or ‘Deficient’ in vitamin D. Children were divided into 3 equal groups. A structured questionnaire, formed of four sections, was answered by the parents. Dental examination was performed under natural daylight. Caries index (dmf), for each group, was calculated then compared. The study was conducted from July 2019 to January 2020. Associations between dmf and different variables were assessed using independent t-test. Correlation between age and dmf was assessed using Spearman’s rank order correlation coefficient. Multiple linear regression model was used to study the effect of different variables on caries.ResultsThere was a weak positive correlation between age and dmf scores (β = 2.00; 95%CI, 0.73:3.26). Children playing outside experienced higher dmf (β = 1.29; 95%CI, -0.35:2.94) than those with no outside play. Children with 25(OH) D below 20 ng / ml had the highest dmfs (β = 1.01; 95%CI, -0.74:2.76). There was a significant association with teeth brushing; children not brushing their teeth showed significantly higher dmf (β = -2.21; 95%CI, -4.14:-0.28) than their counterparts. There were no significant associations of sex (β = -1.05; 95%CI, -2.68:0.59), fluoride tablets intake (β = 2.19; 95%CI, -1.25:5.63), dental visits (β = -1.43; 95%CI, -3.09:0.23), mothers’ vitamin D intake during pregnancy (β = 0.71; 95%CI, -1.13:2.56), snacking (β = -1.18; 95%CI, -4.62:2.26) and parental education (β = 0.62; 95%CI, -1.18:2.42) with caries experience among the study population.ConclusionVitamin D deficiency does not seem to be associated with dental caries experience of 3–5 years old Egyptian children. Out of the indicator variables, age and tooth brushing contributed significantly to the occurrence of dental caries among the study population.