The purpose of this study is to investigate the effect of audit committee characteristics on the level of sustainability reporting of companies listed on the stock exchange with emphasis on agency theory, legitimacy theory and stakeholder theory. The data collection method is archival and to test the research hypotheses, the data of 152 companies listed on the stock exchange that were collected during the period 2014 to 2018 have been used. For data analysis, regression with a combined data approach was used. The Global Reporting Initiative's checklist has been used to measure sustainability reporting. The findings indicate that audit committee characteristics (size, independence, financial expertise and gender diversity of the members) have a positive and significant effect on corporate sustainability reporting level. Evidence suggests that the audit committee is effective as a corporate governance mechanism and control tool in improving the reporting quality in general and sustainability reporting in particular enhance to achieve the stakeholders goals. The findings of this study have important results for compilers of requirements and standards, management of companies and stakeholders. The findings of this study show the importance of disclosure requirements for non-financial information (environmental, governance and social information) for legislators and standardizers. The results of this study improve stakeholder awareness of the importance of corporate social responsibility, corporate governance, and environmental information on credit and investment decisions, and encourage companies to disclose sustainable reporting information in order to play their social role.