Today, threats to the state are changing, from those that were originally only military to non-military threats and even hybrid threats. Therefore, to strengthen the country's defense, Singapore and Indonesia implement the reserve component program by involving the participation of all their citizens, the object of this study is to operate Singapore's reserve component management with Indonesia in supporting the country's defense, The sub-focus of this study is to compare Singapore's reserve component management with Indonesia in supporting the country's defense, and the strengths and weaknesses of component management Reserve. To answer the focus and sub-focus, this research uses qualitative methods of comparison with data collection through interviews, literature reviews, and the design of comparative approaches related to the management of reserve components of the two countries. The results showed significant differences in reserve component management, starting from the registration flow, training, and structure, to the process after personnel went through reserve component activities. It also found advantages and disadvantages in the management of the two reserve components. The recommendations include a development focus on key aspects such as improving the quality, capacity, and reliability of Reserve components. In addition, it is necessary to increase support for the education and career of individuals during military service. By implementing these recommendations, it is hoped that the management of reserve components in both countries can strengthen their national defenses more effectively.