The amount of investment of companies can be caused by several factors. One of these factors is the company's cash flow and, in fact, the amount of financial resources available to finance new projects. how to finance new investments in the company; It is affected by the management's decisions, but in general, it seems that the higher the company's cash flow, the higher its investments. The purpose of this research is to investigate the relationship between managerial optimism and the sensitivity of investment cash flow with the effect of the gender role of the audit committee. The statistical research population of companies admitted to Tehran Stock Exchange and the studied sample includes 140 admitted companies during the years 2015 to 2019. The research method is descriptive and in terms of the relationship between the variables, it is a combination of causality-correlation, and it is practical in terms of the goal. The regression method and panel data as well as the fixed effects model were used to process and test the hypotheses. The results obtained from the analysis of hypotheses showed that managerial optimism has a positive and significant relationship with investment cash flow sensitivity, and the gender of the audit committee has a negative and significant effect on the relationship between managerial optimism and investment cash flow sensitivity.