Introduction: Dental caries remains to be a significant health concern since childhood. Caries prevalence in developing nations has increased due to an array of factors such as diet, low socioeconomic status, exposure to fluorides, ethnicity, age, the limited access to oral health services, and other lifestyle factors. Childhood obesity and physical activity are interrelated and have known to influence dental caries prevalence. Aim: The aim of this study is to evaluate the role of diet, physical activity, and adiposity in children from schools of two different lifestyles and its influence on dental caries. Materials and methods: A cross-sectional study was performed by recruiting 300 children in the age group of 6–10 years. The schools were categorized into two groups: group I—day scholar schools and group II—residential schools. The data regarding the diet, physical activity, and adiposity were collected using a questionnaire given to the child and the parent. Anthropometric measurements of all the children were recorded. Results: The consumption of junk and access to gadgets was greater in group I children compared to that in group II and the amount of physical activity was greater in residential schools. The group I school children were known to be more obese compared to the children from group II and a statistical significance was seen with the caries experience among the two groups. Conclusion: Diet, physical activity, and adiposity could influence the dental caries experience among school-going children.