Nuclear proliferation has become one of the central issues in international relations studies, particularly in the context of military power competition between rival states. This research aims to analyze Pakistan’s military defense strategy against India through nuclear proliferation. The background of this study lies in the issue of nuclear proliferation which has emerged as consequence of technological advancements and interstate conflict, especially between Pakistan and India. Despite its limitations Pakistan seeks to protect itself from potential military threats posed by India by developing its nuclear capabilities. This study examines how nuclear proliferation serves as a form of self-defense for Pakistan, given India’s more advanced military capabilities. The research employs a literature review method referring to previous studies and international agreements such as the Non-Proliferation Treaty (NPT) the role of the International Atomic Energy Agency (IAEA), and Pakistan’s 1973 constitutional policies. Using defensive realism approach and the concept of self-deterrence, this study explains how Pakistan’s nuclear policy has evolved in response to threats from India, which had developed its nuclear weapons earlier. This research contributes to international security studies, particularly in understanding how conflict-prone nations utilize deterrence strategies to maintain regional stability. While nuclear proliferation may escalate geopolitical tensions, the findings suggest that nuclear weapons ownership also serves as a tool for negotiation and war prevention in regions prone to prolonged conflicts. This study indicates that Pakistan’s decision to develop and maintain nuclear technology is not merely and effort to enhance military power but also a strategy to create a balance of power in South Asia. By fostering cooperation with countries like China and receiving military technological assistance, Pakistan ensures its defense remain concrete against India. The result of this study are expected to provide insight into the dynamics of nuclear proliferation between Pakistan and India and its implication for regional stability. Additionally, this research aims to serve as a reference for future academic studies on nuclear proliferation and international relations studies.