Introduction: The fast invereasing trend of adolescent obesity is causing concern in developing countries such as Iran, making Identification of the related factors assential for its control and prevention. The aim of this study was to explain the phenomenon and the factors from the view of obese adolescent girls of urban. Materials and Methods: For this qualitative study, ten focus group discussions were used to collect data from 32 obese girls, aged 12-16 y. All group discussions were recorded and analyzed and classified immediately after focus group discussions. Results: Results showed teens to be dissatisfied with their current situation and obesity although they had positive attitudes towards some basic food groups and to physical activity, they did not have the necessary motivation and self-efficacy for weight control. In their opinion, parents, teachers, peers and mass media played a significant role in the adoption of nutritional behaviors. Conclusion: Educational programs need to be implemented for health promotion and behavioral changes. Using group discussions, the findings of this study can be effective in designing interventions to change lifestyles and prevent obesity in adolescents.