Abstract: Theory of planned behavior (TPB) is the most famous theory about attitude-behavior in social psychology and has been found to be well supported by empirical evidences. According to TPB, intentions to perform behaviors of different kinds can be predicted with high accuracy from attitudes toward the behavior, subjective norms, and perceived behavioral control, account for considerable variance in actual behavior. In this paper, various aspects of TPB were introduced, including its derivation, general picture, measurements, new researches and developments. Other issues that remain unresolved and further studies were discussed in the end

Key words: the theory of planned behavior, behavior intention, attitude toward the behavior, subject norms, perceived behavior control