Background: This study examined the prevalence of overweight, obesity and the association between BMI and Academic performance in Indian school-going adolescents. Methods: A school-based cross-sectional study was carried out in various government and private schools of Madurai District, Tamil Nadu, India to identify the prevalence rates of overweight and obesity among urban schoolgoing adolescents studying in fifth to twelfth classes of both genders. A pre-tested questionnaire was used to elicit information on family and individual characteristics. Height and weight were measured and BMI was calculated. Results: Overall prevalence of overweight and obesity was found to be 1.66 % and 5.05% respectively. The mean BMI of both genders showed a significant decrease with age. Amongst genders, girls had higher mean BMI values within each age group. Statistical results reveal that the changes in body mass index were highly related to academic performance in both of the school setups at a 1% level of significance(Private Schools - __ampersandsignchi;2 = 2.470; Government Schools - __ampersandsignchi;2 =20.051 p__ampersandsignle; 0.00). Conclusion: Academic performance as an adolescent has significant implications for future adult health and social well-being; therefore, understanding factors that contribute to academic achievement are vital for the future success of these adolescents.