This study investigates the influence of individual blockholder on accounting quality. Prior studies investigating Korean blockholders' influence focus on the influence of controlling shareholders or institutional investors; however, they rarely examine individual blockholders’ influence. This paper investigates how individual blockholders in Korean stock markets affect accounting quality of firms listed in Korean Stock Exchange. I analyze individual blockholders' influence on proxies of accounting quality using multivariate regression with hand-collected individual blockholder data. Korean law requires public firms to disclose the list of shareholders having no less than 5% of ownership. From the list of blockholders, individuals who have no explicit personal relation with controlling shareholders were classified as individual blockholders. My empirical results show that firms having individual blockholder(s) use more income-decreasing accruals than those having no individual blockholder. Furthermore, accounting information of firms having individual blockholders(s) is more conservative than that of firms having no individual blockholders. However, the presence of individual blockholder increases the tendency of loss avoidance and earnings management using overproduction and reduction of discretionary expenditure. This paper contributes to the literature by presenting the first evidence of the monitoring role of an individual blockholder on financial reporting of firms listed in the Korean stock markets.