Background: Although preventable, dental caries remain a serious global public health threat. There are a number of risk factors for the development of dental caries in the general population, and in elementary school children in Thailand in particular, especially if they are from suburban areas. Objective: To identify the prevalence of dental caries in the form of decayed-missing- filled teeth for the permanent (DMFT) and primary (dmft) dentition, and their risk factors among children between 6 and 12 years of age attending a public school in Chiang Rai in northern Thailand. Methods: A cross-sectional study was conducted among 6–12-year-old children attending public education at Thesaban 1 School, Chiang Saen District, Chiang Rai Province in Thailand. All school children from grades 1 to 6 were examined by trained dental students from Mae Fah Luang University’s School of Dentistry in December 2023. Children were clinically examined for DMFT/dmft while demographic information about the children was collected from school records. Children also responded to a standardized 17-item survey about their oral health care behaviours. Descriptive and inferential statistics were used. All tests were set at 95% CI and p>0.05. Results: A total of 232 children (100% of eligible participants) were examined and 96 (40%) responded to the survey. Most children were Buddhists (n=186, 80.1%), and had at least one permanent tooth with sealant (n=198, 85.3%); 82.5% of the 232 children exhibited dental caries/extraction/fillings in primary teeth. The average dmft was 4.1 (1.8–8.8) and the average DMFT was 1.6 (0.1–3.3). Fifty children (21.5%) had their grandparents as their main caregiver. Children who brushed their teeth without fluoridated toothpaste were 1.99 times more likely to have at least 1 permanent tooth with dental decay than children who used fluoridated toothpaste (p=0.065). Conclusion: In this study, a high percentage of dental caries was observed among children from suburban areas in the northernmost province of Thailand. Public health intervention and oral health promotion remain an immediate need among these children.