Background: According to the WHO, obesity is a "global epidemic". Obesity is a significant public health issue due to the possibility of difficulties in childhood and the rise in morbidity and mortality throughout adulthood. Objective: to evaluate the prevalence &determinants of obesity using Body mass index, waist circumference & waist height ratio of school going children aged 6 to 18 years. Methods: This Cross-sectional study was done among Children of 6-18 yrs age group in private or government schools of Bareilly, UP. Duration of Study was from 1stAugust 2023 – 31stJuly 2024. Result: we found not a statistically significant association between family members or number of siblingsin the study population, the accompanying condition of living with obesity, and BMI, waist circumference, and waist hip ratio in obese people.We found statistically significant association between snacking and BMI (p-value = 0.005) in obese people by chi square approach. Eating and screen time were strongly statistically associated with waist circumference (p-value = 0.001) and waist hip ratio (p-value = 0.001). Low extracurricular activities showed a substantial statistically significant association with waist circumference (p-value = 0.001), waist hip ratio (p-value = 0.001), and BMI (p-value = 0.001). Waist circumference (p-value = 0.002) and waist hip ratio (p-value = 0.002) showed statistically significant association with the time of morning awakening. Conclusion: Our study's total obesity prevalence falls within the precise same range as other research. Obesity may go undiagnosed if BMI is the sole metric used to measure it. Increased incidence of the obesity is affected by age, gender, parent’s education and occupation, screen time, meals taken during that time, more indoor activities and late morning awakening