The escalating complexity of modern fire risks, coupled with the environmental and performance limitations of conventional solutions, necessitates a paradigm shift in fire safety science. This chapter comprehensively explores the transformative role of nanotechnology in ushering in this new era. It begins by establishing a foundational understanding of the unique physicochemical properties of nanomaterials and delineates their primary mechanisms of action, including barrier formation, catalytic charring, thermal insulation, and smoke suppression, that underpin enhanced flame retardancy. A critical review of major material classes, from carbon-based nanostructures and nanoclays to layered double hydroxides (LDHs) and phosphorus-based composites, is provided, highlighting their structure-property relationships. The discussion then transitions to the application of these advanced materials across critical sectors such as intelligent textiles, high-performance polymers, construction, and electronics, as well as their integration into next-generation fire detection systems and protective equipment. However, the path to widespread adoption is fraught with challenges. The chapter offers a critical analysis of the significant hurdles surrounding scalability, economic viability, environmental health and safety, and the nascent regulatory landscape. Finally, it concludes by mapping future research frontiers, emphasizing the potential of intelligent, responsive materials, the convergence with artificial intelligence and biomimicry, and the imperative for sustainable, green synthesis routes to realize the full potential of nanotechnology in creating safer and more resilient environments.