Worldwide prevalence of obesity among children and adolescents increased substantially over decades. Addressing potential risk factors of obesity among adolescents is very important for a successful intervention program in this population. The present study aimed to identify the sociodemographic determinants of obesity among school adolescents in Terengganu. A cross-sectional survey involving 3,798 school adolescents age 12 years old from 136 government primary schools in Kuala Terengganu and Besut districts were carried out from November 2014 to June 2015. For the purpose of this paper, the data for 2,842 school adolescents classified as either normal BMI (< +1SD) (n= 2,305) or obese (+2SD) (n= 537) based on WHO cut-off points were taken for analysis. Sociodemographic information on subjects and their parents were obtained from self-reported questionnaire. Anthropometric measurements were conducted by Physical Education teachers and uploaded into a specific developed database. The prevalence of obesity was relatively high in both genders in this study. Binary logistic regression analysis found gender, parental BMI, household income, household size and maternal working status were independently associated with obesity among school adolescents in this population. In the final model, being male, having working mother, and having obese parents were identified to be potential risk factors for obesity whilst having large household size lower the risk of obesity among these adolescents. Prevention programs are needed to increase awareness about the risk factors of obesity in adolescent and interventions should now focus on family member as well mainly the parents.