This study explores a comparative analysis of Vietnam and Cambodia as major partners of Korea's Official Development Assistance (ODA), examining the differences in their economic development stages despite both being located within the Mekong sub-region. Additionally, the study evaluates whether Korea's ODA policy aligns appropriately with each country's domestic policies, with a particular focus on the transportation infrastructure sector, which is essential for economic growth and social development. Vietnam, aiming to reach Upper-Middle-Income Country (UMIC) status by 2050, requires large-scale infrastructure projects, while Cambodia prioritizes basic infrastructure development. These distinctions call for a differentiated ODA approach from Korea. To achieve this, Political Economy Analysis (PEA) is utilized to examine the socioeconomic characteristics of each country, and indicators like the GNI (Gross National Income) and the Logistics Performance Index (LPI) are employed to further refine development cooperation strategies. The study also reviews development cooperation cases by Japan and China in the Mekong sub-region to extract strategic insights for Korea. In conclusion, this study emphasizes the need for a tailored, strategic ODA approach that aligns with the transportation infrastructure development stages of Vietnam and Cambodia. It proposes differentiated cooperation plans that consider each country’s unique development needs.