Although finance has been studied for thousands years, behavioral finance which considers the human behaviors in finance is a quite new area. Behavioral finance theories, which are based on the psychology, attempt to understand how emotions and cognitive errors influence individual investors’ behaviors (investors mentioned in this study are refered to individual investors). The main objective of this study is exploring the behavioral factors influencing individual investors’ decisions at the Ho Chi Minh Stock Exchange. Furthermore, the relations between these factors and investment performance are also examined. As there are limited studies about behavioral finance in Vietnam, this study is  expected to contribute significantly to the development of this field in Vietnam.  The study begins with the existing theories in behavioral  finance, based on which, hypotheses are proposed. Then, these hypotheses are tested  through the questionnaires distributed to individual investors at the Ho Chi Minh Stock Exchange. The collected data are analyzed by using SPSS and AMOS soft wares. Semi-structured interviews with some managers of the Ho Chi Minh Stock Exchange are conducted to have deeper understanding of these behaviors. The result shows that there are five behavioral factors affecting the investment decisions of individual investors at the Ho Chi Minh Stock Exchange: Herding, Market, Prospect, Overconfidence-gamble’s fallacy, and Anchoring-ability bias. Most of these factors have moderate impacts whereas Market factor has high influence.  This study also tries to find out the correlation between these behavioral factors and investment performance. Among the behavioral factors mentioned above, only three factors are found to influence the Investment Performance: Herding (including buying and selling; choice of trading stocks; volume of trading stocks; speed of herding), Prospect (including loss aversion, regret aversion, and mental accounting), and Heuristic (including overconfidence and gamble’s fallacy). The heuristic behaviors are found to have the highest positive impact on the investment performance while the herding behaviors are reported to influence positively the investment performance at the lower level. In contrast, the prospect behaviors give the negative impact on the investment performance.