The investment decision, a critical decision for each investor as it involves risks and uncertain returns, so investors should avoid cases of uncertainty associated with the final decisions they are involved, and the problem of research in individual differences and differences in the behavior of individual investors and reflect the impact of this investment decision in the Iraqi market for securities. Therefore, the research aims to understand and analyze the impact of determinants of investor behavior as an independent variable in investment decision-making as a dependent variable in the Iraqi market for securities, and the research started from two main hypotheses to explore the influence and correlation between research variables Through the analysis of the responses of the research sample (385) individual investor, present in the Iraq Stock Exchange, and the tool used to collect data (questionnaire), the data were analyzed using the Statistical Package for Social Sciences (Spss – V.19) and a set of statistical methods (Such as arithmetic mean, standard deviation, coefficient of difference, relative importance, simple and multiple regression equations, t-test, f-test, and Pearson correlation coefficient). The research reached a number of important conclusions, and the presence of a positive and moral impact to the determinants of the behavior of the investor (personal, learning, trends, motivation perception, needs, ethics) in the investment decision in the Iraqi market for securities, and the most important recommendations, the need for further studies in the study and analysis of the behavior of the investor and identify the most important dimensions affecting the investment decision in the Iraqi market for securities, and the market concerned to increase the awareness of the investor and its focus on the most important determinants and implications resulting in his investment decision, and not to minimize or omit any of them when looking at the decision-making process for an investment, but are equally important, as a result of mistakes which it is located.