This research investigates The effects of accounting conservatism bias in management Overconfidence Over confidence of population of listed companies in Tehran Stock Exchange has been studied. To this end, the following regression models and Dvlmn A. (2012), the issue was investigated. Data models of the company were collected during the field research period from 1380 to 1390 -10 years- its shares were offered at Tehran Stock Exchange and its stock trades on the over three months is not interrupted. Thus, 101 participants were selected as a sample. We find there is no relation between Accounting Conservatism and Managerial Overconfidence.