Background: Between 2017 and 2021, the prevalence of obesity among children aged 2-19 years reached 19.7%, affecting approximately 14.7 million children, with rates of 12.7% among those aged 2-5 years and 22.2% among those aged 6-11 years. Globally, dental caries is among the most common non-communicable diseases, often leading to pain, infection, tooth loss, and reduced quality of life. In Mongolia, the prevalence of overweight and obesity among children and adolescents has increased markedly since 2010, beginning at an early age. In 2018, one in six children under five years and one in eight adolescents were overweight. Aim: This study aimed to assess selected non-communicable disease risk factors among children and adolescents. Materials and Methods: A cross-sectional study was conducted in Ulaanbaatar, Mongolia, using Family Health Centers across all nine districts. A total of 622 children aged 6–17 years were included. Anthropometric measurements (weight, height, and waist circumference) were obtained, and body mass index (BMI) was calculated. Oral health examinations were performed to determine the Decayed, Missing, and Filled Teeth (DMFT) index. Nutritional status was classified based on age and sex-specific growth charts into normal weight, overweight, and obesity categories. Results: Among the participants, 10.29% (n=64) were overweight and 9.97% (n=62) were obese. Overweight was more prevalent among girls, whereas obesity was relatively higher among boys (p<0.001). Regarding dental caries, 37.6% (n=234) of participants had no caries (DMFT=0), 48.1% (n=299) had mild caries (DMFT=1-2), and 14.3% had moderate to severe caries (DMFT≥3). The overall prevalence of dental caries was 62.38%, with significant variation by age group: highest in children aged 6-9 years (69.9%) and lowest in those aged 15-17 years (46.1%) (p<0.001). No statistically significant association was found between BMI categories and dental caries status. Although normal weight predominated in the DMFT=0 and DMFT=1-2 groups, logistic regression adjusted for age and sex showed no significant relationship between BMI and dental caries. However, children aged 6-9 years had a significantly higher likelihood of having dental caries compared to those aged 15-17 years (OR=0.39, 95% CI: 0.24-0.63, p<0.001). Conclusions 1. Among the risk factors for non-communicable diseases (NCDs), overweight and obesity were highly prevalent among children, with one in every five children classified as overweight or obese. The prevalence among male children was approximately two times higher than that among female children (p<0.001). 2. The prevalence of dental caries among the study participants was 90.7%, with a mean caries intensity of 6.4, indicating high level of severity. Age-group analysis demonstrated that children aged 6–10 years exhibited the highest prevalence and severity of dental caries, with a prevalence of 93.5% and a mean caries intensity of 7.3.