This research study evaluated the extent to which psychological factors (overconfidence, confirmation bias) effect on investor’s decision-making process. The ultimate objective of the current study is to investigate the effect of psychological factors on investor investment decision making. To achieve this objective, this study used quantitative approach and cross-sectional research design. Survey was used to collect the data. Questionnaires were distributed among the individual investors and brokers of stock exchange in Pakistan. Smart PLS 3 was used to analyse the data. It was found that overconfidence and confirmation bias have significant effect on investors investment decision making. Moreover, it is found that religiosity has moderating effect between the psychological factors and investors’ investment decision making. Majorly, the current study contributed by investigating the moderating role of religiosity between psychological factors and investor investment decision making.