This paper empirically examines the effect of corporate governance on MDQ(materiality disclosure quality), especially the interaction effect between CEO power and characteristics of the board of directors. The results of this study are as follows: DUALITY (CEO and chairperson are the same person) negatively affect the MDQ but CEO tenure did not significantly affect the MDQ. Board Size has a significant positive relationship with the MDQ, whereas Board Independence had no significant effect on the MDQ. The activities of the audit committee have a no significant association with the MDQ. We find that MDQ tends to increase when non-DUALITY are combined with large size of the board of directors. Next this study confirmed that the relationship between governance and MDQ varies depending on the report type. The contribution of the study is, first of all, that we are the first to show that the interplay between powerful CEOs(non-DUALITY) and the size of their boards, also the results could be beneficial for a number of users of non-financial information, such as regulators, investors, auditors and NPO/ NGOs to make better decisions.