<p>Dental caries is the most prevalent chronic disease in children, and genetic factors significantly contribute to its development. The study aimed to investigate the association between the miR-155 rs767649 polymorphism and the risk of dental caries in Chinese Han children. 165 children with dental caries and 165 caries-free children were recruited. The rs767649 polymorphism was genotyped using the TaqMan probe method, and miR-155 expression was quantified by RT-qPCR. Logistic regression analysis was performed to evaluate the association between genotype and caries susceptibility. miR-155 expression was significantly elevated with dental caries children. The TT genotype (OR = 2.271, 95% CI = 1.399–3.685, <i>P</i> &lt; 0.001) and the T allele were associated with an increased risk of dental caries. Within the caries group, individuals with the TT genotype exhibited significantly higher miR-155 expression than those with the AT+AA genotypes. No significant differences in miR-155 expression were observed among different genotype groups in the healthy control group. Additionally, the TT genotype was associated with a more severe degree of dental caries (higher dmft and dmfs scores), and miR-155 expression showed a significant positive correlation with both dmft and dmfs scores. Furthermore, the use of fluoride toothpaste and regular dental visits may reduce the incidence of dental caries, whereas sweet food intake, elevated miR-155 expression, and the TT genotype of rs767649 were identified as risk factors. The polymorphism of miR-155 rs767649 was significantly associated with an increased susceptibility to dental caries in Chinese children.</p>