Grip strength (GS) is used as an index of overall health in children. The objectives of our study were to assess GS, gender differences in GS in 9 -18 year old urban (U) and rural (R) Indian children, study association of GS with body composition (BC) and assess determinants. This was part of a multicentre, cross sectional, school-based study (n=1978, mean age 13.3 ± 2.2 years) from 3 U and R states. Anthropometry, BC, dietary intake, physical activity, sunlight exposure and GS (in Kg) measurements were performed. The mean GS increased with age but plateaued in girls after 12 years; was higher in boys (19.6 ± 9.2) than girls (14.3 ± 5.3) (p < 0.05). Mean GS was higher in U (21.05 ± 9.7) than in R boys (17.8 ± 8.2) (p < 0.05), comparable in U (14.9 ± 5.2) and R girls (13.8 ± 5.5). GS in girls remained lower than boys after adjusting for muscle mass (MM). Difference between boys and girls reduced after body size (BMI) correction, but remained low in girls plateauing after 15 years. MM and age were significant determinants of GS in all children. On addition of lifestyle factors, GS was explained to varied degrees, the least in U girls, followed by R girls and R boys and the most in U boys. Conclusion: In boys, nutrition though body size and composition was largely responsible for the differences in GS and in girls, additionally socio-cultural factors also possibly impact GS.