The Official Development Assistance (ODA) is Japan’s salient foreign policy in the Lower Mekong Basin (LMB) Country, especially for industrial human resource development. Japan has established KOSEN, a Japanese engineering vocational education system in the region to promote the industrial acceleration agenda and the region’s economic, social development, and poverty reduction toward the 2030 Agenda of Sustainable Development Goals (SDGs). However, ODA is about more than giving and receiving; it is about actors and administration, including the vis-à-vis mutual benefit for both donor and recipient country, which becomes a debatable issue. This research intends to shed light on the efficacy of Japanese ODA toward LMB by applying the principles of the Paris Declaration on Aid Effectiveness (2005) and its impact on the Sustainable Development Goals (SDGs) attainment. A qualitative technique with a deductive approach was used to analyze the efficiency of Japan’s aid for KOSEN, including an in-depth interview with a purposive sampling technique of three key informants in this study. The study showed that the donor country predominantly adheres to the assistance ownership concept. Nonetheless, developing the KOSEN system as an assistance program in the area can contribute to the SDGs as hard tool mechanisms and KOSEN values as a soft mechanism related to the 2012 Global Agenda for Greening TVET.