This study aimed to develop a validated and reliable food frequency questionnaire (FFQ) that assess dietary intake related with dental health in children. Children, two-to-nine-years old, who consulted to a paediatric dental clinic for any reason, were recruited to complete the FFQ and 24-h recall, inquired oral hygiene habits, performed oral examinations, recorded dmft(s)/DMFT(S) index, and taken anthropometric measurements. The statistical methods used for validation were Wilcoxon signed rank test, Spearman ranked correlations, weighted kappa statistic and Bland-Altman graphs were drawn. Besides, intraclass and spearman correlation coefficients calculated for the reliability. A total of 120 children participated in to the first stage of the study while 70 participants completed the 4-month period. The Spearman correlation coefficient and weighted kappa values confirmed that the FFQ had moderate validation against the food records for lactose, calcium and phosphorus. Dietary fat, fibre, lactose, calcium, potassium, fluoride, magnesium, phosphorus and zinc intakes were negatively and statistically significantly correlated with DMFT and DMFS according to both FFQ and 24-h (p<0.05, for each). Furthermore, a positive correlation between DMFT/S and dietary carbohydrate, starch, polysaccharide and sucrose intakes was obtained. These results provide the preliminary evidence for the moderated reliability and validity of the FFQ; the higher DMFT and DMFS scores might be linked to lower dietary intakes of fat, fibre, lactose, calcium, potassium, fluorine, magnesium, phosphorus and zinc; and probably higher dietary intakes of carbohydrate, starch, polysaccharide and sucrose in children.