Purpose: The purpose of this study was to develop a system dynamics model for adolescent obesity in Korea that could be used forobesity policy analysis. Methods: On the basis of the casual loop diagram, a model was developed by converting to stock and flowdiagram. The Vensim DSS 5.0 program was used in the model development. We simulated method of moments to the calibration ofthis model with data from The Korea Youth Risk Behavior Web-based Survey 2005 to 2013. We ran the scenario simulation. Results:This model can be used to understand the current adolescent obesity rate, predict the future obesity rate, and be utilized as a toolfor controlling the risk factors. The results of the model simulation match well with the data. It was identified that a proper model,able to predict obesity probability, was established. Conclusion: These results of stock and flow diagram modeling in adolescentobesity can be helpful in development of obesity by policy planners and other stakeholders to better anticipate the multiple effectsof interventions in both the short and the long term. In the future we suggest the development of an expanded model based onthis adolescent obesity model.