Managers are motivated to keep the funding ratio of a firm's defined benefit (DB) pension plan from reaching its optimal level. This phenomenon can be explained by agency theory, which suggests that agency costs can be mitigated by a good governance structure. This study analyzes the effect of a firm's corporate governance on the funding of its defined benefit corporate pension plan. The funding ratio is measured as the ratio of the current value of the plan's assets over the pension benefit obligations (PBO). The sample includes 478 companies listed on the Korea Composite Stock Price Index from 2006 to 2018. The results indicate that firms with better governance tend to have higher funding ratios. As South Korea lacks mandatory regulations requiring firms to keep their pension funding ratio above a minimum level, firms can keep their ratio low. Good governance implies that a manager is required to maintain a higher ratio. In addition, sub-structures of governance, defined as components constituting the overall governance, have a meaningful relationship with the funding ratio. Important sub-structures include the ownership structure, the board of directors, and the labor union. This study has the following findings. First, a firm's pension ratio increases with its corporate governance index. This result is stronger after controlling for the size of the firm. An implication of this finding is that good governance mitigates the agency problems of outside equity and debt, increases the funding ratio, and enhances firm value. Second, a firm's pension funding ratio increases with the managers' share-holding ratio. This result suggests that the managers decide to accumulate more pension assets as their interests become better aligned with those of shareholders. Thus, the ownership structure is an important component of the governance structure in that it affects the corporate pension policy. This paper also investigates the influence of outside shareholders on the funding ratio. Active outside shareholders are expected to monitor managers and mitigate the managerial incentive problem. The funding ratio increases with the foreign investor share ratio, which is a proxy for the extent of the alignment of interests between the managers and the outside shareholders. A fourth finding is that the funding ratio increases as the proportion of outside directors on the board increases after controlling for a nonlinear term. This result implies that firms are more active in accumulating pension assets if their board of directors are independent of the managers and so are more able to successfully mitigate the agency problem. Fifth, this paper measures the bargaining power of labor unions by looking at their affiliation with a nation-wide umbrella organization. A direct measure of labor'sthe bargaining power of labor, such as whether an individual firm has a labor union, is not practical, as almost all firms have labor unions. Affiliation with an umbrella union does not improve the funding ratio. SEuch an affiliation either fails to help the union enhance its bargaining power or it leads the union to engage in political issues instead of benefittingsupporting employees. These results are tested for robustness by adopting various specifications of the primary regression model. The alternative specifications include using alternative measure of the funding ratio, introducing lagged independent variables, controlling for endogeneity, performing sub-sample analyses, and using the funding ratio in excess of the relevant yearly industry average as the dependent variable. In South Korea, firms appear to have an incentive to underfund their defined benefit pension plan in the absence of mandatory regulation on the minimum funding level. This study suggest that better corporate governance mitigates various types of agency problems and thereby enhances firm value as a result of higher pension funding levels. In future work, it would be worthwhile to conducting a comprehensive study of the optimal level of pension funding. In general, if a firm's pension funding level is too low, thereit may experiencebe agency problems or financial constraints at the firm; if a firm's pension funding is above the optimal level, the its cash is being used inefficiently. An in-depth analysis of the labor union factors likely to be overlooked in corporate governance would also be beneficial. Studies could also examineing the relationship between corporate governance and pension asset management. There is growing controversy regarding the reasons behind the persistently dominant holding of interest-guaranteed assets over other types of assets by defined benefit pension plans. Researchers should also examine the introduction of a fund-type pension plan in addition to a contract-type pension plan, which is currently being discussed in South Koreais .