With the discovery and global expansion of nuclear energy, the need for an international nuclear law framework has emerged. Thus, realizing the advantages of the safe, secure, and peaceful use of nuclear technology and its applications in our daily lives depends on an inter- national nuclear law framework. According to International Atomic Energy Agency (IAEA) nuclear law stands on four main ‘pillars’: nuclear safety, nuclear security, nuclear safeguards and liability. This study aims to trace the development of international nuclear law focusing particularly on its four-pillar structure. To this end, the study first examines the concept of international nuclear law, and then respectively focuses on nuclear safety, nuclear security, nuclear safeguards and civil liability for nuclear damage within the framework of international nuclear law. In this regard, the work of the IAEA, the world’s international nuclear watchdog, towards ensuring that nuclear science and technology are used in a safe, secure, and peaceful manner has been assessed. The study also puts that all four pillars of international nuclear law has been expanded and improved due to the need in process and the particular challenges they have faced.