Voluntary disclosure of information leads to capital market efficiency and increases shareholder confidence in the company. The effectiveness of the audit committee and the quality of the audit can improve the quality of discretionary disclosure. The present study investigates the effect of the audit committee and the quality of the audit on the quality of voluntary disclosure of companies listed on the Tehran Stock Exchange. This research is applied in terms of purpose and in terms of methodology of correlation is causal (post-event). Using systematic elimination sampling method, 120 companies were selected as a sample of the research in a period of 6 years between 1392 to 1397. The method used to collect information is a library and the relevant data for measuring variables were collected from the Cadal site and the companies' financial statements. Preliminary calculations were performed in Excel and then Stata software was used to test the research hypotheses. The results show that the size of the audit firm affects the quality of voluntary disclosure. However, the auditor's tenure and the auditing fee do not affect the quality of the voluntary disclosure. The financial expertise of the audit committee does not affect the quality of the voluntary disclosure. The experience of the audit committee does not affect the quality of voluntary disclosure. The independence of the audit committee does not affect the quality of voluntary disclosure.