Topicality. Given the geopolitical situation, where Ukraine faces threats to its sovereignty and territorial integrity, ensuring defense capability becomes the most important task. The development of modern technologies in the defense industry, including Industry 4.0, emphasizes the need to supply the Ukrainian army with high-quality foreign equipment and technologies. Cooperation with leading international corporations in the defense sector opens up opportunities for technology exchange, investments, and the integration of new possibilities for the development of the Ukrainian defense industry.Ukrainian machine-building enterprises possess significant potential in the production, repair, and modernization of military equipment, which can be utilized to meet the army's needs. The gradual localization of Western technology production in Ukraine will contribute to reducing dependence on imports and increasing production volumes. The development of the service, repair, and restoration sector of military equipment can positively impact employment and the socio-economic situation in regions of Ukraine.In particular, the development of modern defense potential is a strategically important task for any state. Ensuring the availability and effective use of modern military technology is a necessity for maintaining a peaceful atmosphere and national security. Collaboration with leading international companies and the implementation of modern production technologies equate Ukrainian machine-building to global leaders, opening the way for foreign investments and the development of new technological sectors in Ukraine. The implementation of Industry 4.0 and collaboration with international partners allow for a significant improvement in the technical level and efficiency of Ukrainian armed forces, ensuring their readiness to face challenges and threats. The development of innovative management technologies and production culture provides Ukrainian enterprises with a competitive advantage in the global market, promoting their further growth and development.Aim and tasks. The aim of the research is to analyze and assess the potential of the machine-building cluster in the context of ensuring Ukraine's defense capability in a complex geopolitical environment.The research tasks include: conducting an analysis of the current situation in development of machine-building clusters in Ukraine and the necessity of implementing modern technologies in machine-building ; evaluating the role and potential of the machine-building cluster in ensuring the defense capability of the country; analyzing the possibilities of cooperation with leading international companies in the defense industry; studying the capabilities of Ukrainian machine-building enterprises in the production, repair, and modernization of military equipment; developing the key provisions of the strategy for the gradual localization of Western technology production in Ukraine; analyzing the impact of the development of the service, repair, and restoration sector of military equipment on the socio-economic situation of the country's regions based on the implementation of modern technologies and management practices to enhance the competitiveness of Ukrainian machine-building enterprises.Materials and Methods. This study explores the advantages and prospects of forming machine-building clusters, their impact on the socio-economic development of the country, and the enhancement of defense capabilities through the use of comparative, systemic-structural, analytical, theoretical generalization, and empirical observation methods.Research results. The research has established that the machine-building cluster in Ukraine possesses significant potential for ensuring the country's defense capability within a complex geopolitical context. It is emphasized that collaboration with leading international companies in the defense industry provides opportunities for technology exchange, investment attraction, and enhancement of the Ukrainian defense production potential. This is due to the fact that Ukrainian machine-building enterprises have substantial capabilities in the production, repair, and modernization of military equipment, which can be utilized to meet the army's needs. Additionally, the gradual localization of Western technology production in Ukraine will contribute to reducing dependence on imports and increasing production volumes.Conclusion. The research findings attest to the significance of the machine-building sector cluster in the context of ensuring Ukraine's defense capability. Collaboration with international partners and the implementation of modern production technologies are key factors in enhancing the competitiveness and expanding the potential of the Ukrainian defense industry. The development of this sector is a strategically important task for ensuring national security and strengthening Ukraine's international standing.