Objective. To identify factors associated with overweight/obesity among adolescents in Ho Chi Minh City, Vietnam. Methods. In 2004, a cross-sectional survey was conducted using multi-stage cluster sampling. Weight and height of 2 678 students from 31 junior high schools in Ho Chi Minh City were measured. Dietary intake and physical activity were assessed using a validated food frequency questionnaire and a physical activity questionnaire. Parental, household and neighbourhood characteristics were also collected. Factors associated with overweight/obesity in adolescents were modelled using hierarchical, multivariate logistic regression. “Survey commands” in STATA were used to account for the multi-stage cluster sampling design. Results. After adjusting for other study factors, the odds of overweight/obesity was significantly higher for male gender (OR=3.1, 95% CI: 1.8, 3.8), younger age (OR=3.4, 95% CI: 2.1, 5.3), schools located in wealthy districts (OR=2.5, 95% CI: 1.8, 3.4), higher family economic status (OR=1.9, 95% CI: 1.1, 4.9), higher parental education (OR=2.0, 95% CI: 1.4, 2.9), overweight or obese parents (OR=3.5, 95% CI: 1.7, 7.0), more time spent watching TV (OR=4.3, 95% CI: 1.3, 14.7), frequent consumption of soft drinks (OR=3.0, 95% CI: 1.6, 5.3) and more time studying after class (OR=2.9, 95% CI: 1.7, 4.9). The odds of overweight/obesity was lower with the availability of fruit at home (OR=0.5, 95% CI: 0.3, 0.7), frequent consumption of fruit/vegetables (OR=0.3, 95% CI: 0.2, 0.4) and being physically active (OR=0.5, 95% CI: 0.4, 0.8). Conclusions. Family/parental factors as well as children's lifestyle should be taken into account when planning interventions to prevent adolescent obesity.