This research aims at verifying the impact of corporate governance mechanisms on the performance of the financial market. Therefore the corporate governance is addressed, including its tools to reach disclosure and achieve the efficiency of the financial market, as well as the concept of accounting disclosure as one of the main principles and pillars of corporate governance and modern economy, The research targeted the practices of corporate governance in Iraqi companies, and the role of corporate governance practices on the performance of the Iraqi stock market through the quality of accounting disclosure as a mediating factor. Hence, it can be said that corporate governance, with its mechanisms and through the principle of disclosure and transparency, is one of the pillars of raising the efficiency of the stock market and achieving a fair price for shares, The study of various factors that may affect disclosure was addressed, to determine the elements that overlapped and affected the level of disclosure in the annual reports The researcher used (STATA) statistical program to analyses the indicators of the companies financial statements, determine the type of relationship between the mechanisms of corporate governance, the quality of accounting disclosure and their impact on the performance of the Iraqi financial market. The study population consisted of a sample of the 35 companies listed in the Iraqi Stock Exchange, which are non-financial companies distributed in four different sectors, namely (services, hotels and tourism, industry and agriculture) whose shares were traded during the period between 01/01/2010 and 31/12/ 2018. The results of the study showed that there is an impact of corporate governance mechanisms on the market performance variables and accounting disclosure. However, the results also revealed that there is no effect of accounting disclosure variables as a mediating factor on market performance variables, The study recommended that the Iraqi Stock Exchange should be in alignment with developments in the Arab markets and hold training courses to increase knowledge and expertise on the subject of accounting disclosure and corporate governance.