This study examines the effect of corporate governance designed to alleviate agency problems on accounting information quality, extending existing research in two aspects. First, while prior research on corporate governance has focused on the board of directors or the audit committee, this study focuses on shareholders. Second, the financial statements comparability is used as a proxy for accounting information quality. The reason why we conjecture that the cross-sectional comparability of accounting information will vary according to the degree of shareholder power against the top management is as follows. The top management, the agent, will change his or her behavior depending on the degree of surveillance of the shareholder, the owner. Meanwhile, ordinary shareholders who have less expertise than professional investors or foreign investors who have less understanding of accounting-related regulations and practices than domestic investors are more likely interested in the comparability of accounting information in order to reduce information processing costs and thereby improve investment efficiency. Therefore, in an environment where this type of shareholders exert a strong influence on top management, they will require a firm to build an accounting system that can produce comparable accounting information in both cross-sectional and time-series manners. In this study, we use (1) the level of protection for ordinary shareholder rights and (2) the relative portion of shares of foreign investors as the proxies for the monitoring environment against top management. The financial statements comparability is measured according to the method introduced in De Franco et al.(2011). The results show that companies whose ordinary shareholders are protected more strongly have a significantly higher financial statements comparability, suggesting that shareholders' monitoring can play an important role in producing relevant accounting information. In particular, the financial statements comparability appears to be closely related to voting rights rather than economic rights, suggesting that in order to produce useful accounting information, companies should focus on improving the effectiveness and convenience of voting rights of ordinary shareholders. On the other hand, foreign investors ownership itself does not have a significant effect on the financial statements comparability. This result appears to deviate from the previous studies documenting that there is a positive relationship between the foreign investor ownership and the quality of accounting information. It is presumed to be due to the fact that the financial statements comparability is relatively ineffective attribute for foreign investors, most of which are institutional investors, because it is not a direct measure of accounting information, but rather a attribute to improve the investment efficiency. Given this fact, our findings are not necessarily in conflict with prior studies. This study provides related studies with a new perspective by focusing on shareholders that have not been covered much in corporate governance research, and investigating the association between shareholders power and financial statements comparability that might be of interest to ordinary shareholders and foreign investors. Given that the emphasis is more and more on providing capital market participants with relevant information to help their investment decision making, the findings of this study, which suggests several important considerations in the process of corporate governance design, have practical and policy implications.