The Theory of Planned Behavior has been shown to yield great explanatory power in health behavior as well as social behavior. This study was conducted to test the Theory of Planned Behavior in the prediction and intention of smoking cessation behavior in university student smokers. We conveniently sampled 204 university student smokers and investigated using questionaries, analyzing the data with the Pearson product-moment correlation, and multiple regression. The results are as follows : 1. There are significant correlations in direct and indirect measures of attitude toward smoking cessation behavior, subjective norm, and perceived behavioral control. 2. Behavior belief is significant in predicting attitudes toward smoking cessation behavior. Normative belief is significant in predicting the subjective norm. Control belief is significant in predicting perceived behavioral control. 3. Attitude toward smoking cessation behavior, subjective norm are significant in predicting intention of smoking cessation behavior. In conclusion, this study demonstrated strong support for the Theory of the Planned Behavior and its use to predict smoking cessation behavior in university students smokers. But, as perceived behavioral control is not significant in predicting smoking cessation behavior, indepth research is needed to evaluate the usefullness of the Theory of Planned Behavior and Reasoned Action Theory.