In 1992, the Korean stock market opened to foreign investments, and since then, shareholdings of foreign investors in Korea steadily increased to a level of over 30% of the total market capitalization. Consequently, they contributed to the growth of the Korean stock market to be ranked recently within the top 10 largest stock markets in the world. Such a steady increase in foreign ownership in Korea helped improve corporate governance systems and streamline the management processes; however, controversies surrounding the outflow of national wealth were provoked in the process of international speculative funds taking over domestic firms in a hostile manner. Now that it has been 25 years since the stock market opening to foreign investments, it is crucial to review the literature on the impact of market opening and foreign investors and seek its implications for a further growth of Korean stock markets. Accordingly, this study discusses an integrative review of recent research in the following four areas. First, an examination of how foreign ownership evolved over time is carried out, and a summary of several representative cases for the hostile takeovers of domestic firms by international speculative funds is provided. Second, this study reviews previous research on the benefits and costs of Korean stock market opening and provides insights on the future directions of financial globalization. Third, a summary of the discussion on the impacts of foreign investors on the governance, dividend, and investment decisions of Korean firms is provided, along with insights on the impacts of foreign investors in Korea. Fourth, this study examines the investment behaviors of foreign investors and reviews their investment performance and evaluates whether foreigners have superior information advantages over domestic investors. Finally, future research directions are discussed by integrating the reviews on the research findings discussed above.