The readability of financial reporting indicates the transparency and effectiveness of information disclosure by company managers. The management characteristics of the company, and especially the CEO, are effective on the readability and understandability of financial reporting. Considering the necessity of having managers with financial knowledge according to the model articles of association of registered companies approved by the Tehran Stock Exchange, as well as the role of CEOs in how financial reporting is prepared and its content, the purpose of this research is to investigate the impact of the CEO's financial knowledge on the readability of financial reporting. In this applied research with a deductive-inductive approach, data from 116 companies listed on the Tehran Stock Exchange during the years 2017 to 2024 were collected, and the research hypothesis was tested using a panneled data approach and applying multiple regression. The empirical results of the research, using the FOG index, indicate that the CEO's financial knowledge has a positive and significant impact on the readability of financial reporting. Also, the results of robustness test, using the number of pages of the board of directors' report, showed that the CEO's financial knowledge has a positive and significant impact on the readability of financial reporting.The results show that the members of the company's board of directors should pay close attention to the academic qualifications of managers, with emphasis on financial and accounting fields, when selecting a CEO.