Theorical effects of accounting disclosure on stock return, Jin and Myers (2006) explain synchronicity and stock crash risk. Specifically, if firm has a better disclosure standard, investors will have more motivation to aggregate firm’ ؛ s specific information and apply this information in in stock price. In addition, if firms have a weak disclosure policy, it shows that management hide some information and in case that cost of hiding information is high, firm disclosure this information suddenly which leads to stock price crash. Thus, the aim of this study was to the effects of information disclosure on stock return synchronicity and stock crash risk with Emphasis the quality of corporate governance in firms listed in Tehran stock exchange. The results of regression analysis for 83 firms indicates that accounting disclosure has a positive significant impact on stock return synchronicity. In addition, the results indicate that accounting disclosure has not a significant effect on stock crash risk. Further results show that corporate governance has not a significant impact on the relationship between accounting disclosure and stock price crash. Finally, the results of the research indicate that the quality of corporate governance has not a significant impact on the relationship between the accounting disclosure and stock crash risk. Totally, the results certify specialty of Tehran Stock Exchange information that indicate low information content because information do not available for all stock market participant.