SUMMARY
In this study, the interaction of audit quality and ownership structure on earnings management of listed firms on Tehran Stock Exchange is studied. In this research, the auditor reputation, auditor tenure, ownership concentration and institutional ownership as a indicator of audit quality and ownership structure have been used. Also, the absolute value of discretionary accruals model of Modified Jones (1995) as a direct indicator of earnings management have been used. In order to respond the questions of this study, four hypothesis has been made and 100 firms from listed firms on Tehran Stock Exchange 5 years (2009-2013) has been tested. This study is descriptive of correlation type and to test the hypotheses, multiple linear regression model with panel data and fixed effects is used. The results of research hypotheses show that, ownership concentration weaken the negative impact of auditor reputation and auditor tenure on earnings management. Also, institutional ownership amplifies the negative impact of auditor reputation and auditor tenure on earnings management. The results of this study could be argued that, the establishment of an effective corporate governance system in Shadow of the interaction between the measures of auditor reputation, auditor tenure and institutional ownership, earnings management will reduced.