A bstract Aim To determine the changes in the sequence and age of eruption of permanent teeth in 5–15-year-old schoolchildren, correlating their dental and chronological age. Materials and methods A total of 1,477 schoolchildren aged between 5 years and 15 years were examined for the eruption timing, body mass index (BMI), and other oral findings. Dental age was calculated for 10% of the total sample using the Willem's method from their ortho-pento graphs (OPGs) and correlated with their chronological age. Results The maxillary teeth erupted earlier than mandibular teeth. Males were found to mature earlier than females. The sequence of eruption observed was: males (maxilla) 1-6-2-4-3-5-7 and (mandible) 1-6-2-3-4-5-7; females (maxilla) 6-1-2-4-3-5-7 and (mandible) 1-6-2-3-4-5-7. The chronological age and the dental age were found to be different in the age range of 9–10 years female; 10–11 years male; and in 13–14 years both male and female. Also when the dental age was correlated with the BMI, the dental age of obese children in 5–6 years and underweight children in 10–11 years were found to be far ahead of their actual chronological age. Conclusion This study opens an expected door for a large sample size to be tested in various local populations with different ethnicity and race as there can be changing trend in the eruption pattern. Clinical significance Changing trends in the sequence and age of eruption of the permanent teeth definitely need to be looked into. As this change, if firmly established in future, can help pedodontist in better planning of space management, interceptive as well as full-mouth orthodontic treatment which largely depends on this sequence being true in most of the cases. How to cite this article Khan AS, Nagar P, Singh P, et al . Changes in the Sequence of Eruption of Permanent Teeth; Correlation between Chronological and Dental Age and Effects of Body Mass Index of 5–15-year-old Schoolchildren. Int J Clin Pediatr Dent 2020;13(4):368–380.