ABSTRACT This study explores how the Japanese and Korean governments use multi-bi aid to complement their bilateral aid and compares their allocation behaviors. As opposed to traditional multilateral aid, multi-bi aid is earmarked for a specific country, project, region, sector, or theme. Japan—a traditional leading donor—and Korea—a small but growing donor—are considerably different in terms of their ODA history and size; although, they are comparable in meaningful manners in terms of their level of cooperation with multilateral organizations. Over the past 10 years, both countries used the multilateral system to a significantly lesser extent yet showed a higher proportion of earmarked funding within multilateral aid compared to the average DAC donor. This study identified more similarities than differences between Japan and South Korea—both countries commit a large proportion of their multi-bi to fragile and conflict-affected states, countries under-represented in their bilateral aid programs. Accordingly, a large proportion of their aid has been channeled through multilateral organizations leading the sectors that are not prioritized with their bilateral aid. Overall, this study identified strong complementarities between the composition of Japan’s and Korea’s bilateral and multi-bi aid.