Dental caries and obesity are two of the most prevalent health conditions affecting children. Relative decrease in corporeal movements, escalating inactive lifestyles, and changes in dietary factors are strongly linked with the increasing incidence of overweight and obesity. Furthermore, obesity increases the risk of chronic disease and dental caries that significantly affects the quality of life of young children. The present study intends to explore the relationship between dental caries and obesity in children in Al-Kharj city, Kingdom of Saudi Arabia. The present descriptive study was designed as a cross-sectional study in which a total of 386 children in the age range of 6 to 12 years from elementary schools of Al-Kharj city and pediatric dental clinics in Prince Sattam Dental College were included. Mean decayed filled teeth (DFT) score was found to be considerably higher among obese children. Also, incidence of dental caries in deciduous dentition was found to be notably higher among obese children. Obesity has a considerable outcome on prevalence of dental caries among primary schoolchildren in Al-Kharj city, Kingdom of Saudi Arabia. The importance of obesity is limited not only to systemic disorders but also in relation to carious lesions. Hence, educating primary schoolchildren about caries and its related factors is very important. High intake of free sugar is a well-established risk factor for dental caries and also for obesity. Therefore, it is speculated that factors that decrease these risk factors have the potential to affect both conditions at the population level to control it competently.