Nitrogen-doped graphene (N-G) and its composites have emerged as promising next generation catalysts and catalyst supports for various fuel cell technologies, offering an effective alternative to costly platinum group metal systems. This chapter provides a comprehensive overview of the performance, mechanisms, and challenges associated with integrating N-G into different fuel cell architectures including proton exchange membrane fuel cells, anion exchange membrane fuel cells, direct methanol fuel cells, microbial fuel cells, and other advanced configurations. The incorporation of nitrogen atoms into the graphene lattice modulates its electronic structure and introduces chemically active sites that facilitate key electrochemical processes such as the oxygen reduction reaction while improving conductivity, hydrophilicity, and structural stability. Furthermore, N-G serves as a robust support for metal and alloy nanoparticles, enhancing metal dispersion and durability through strong metal–support interactions. Experimental evidence demonstrates that N-G based catalysts and supports can deliver higher power densities, superior methanol tolerance, and longer operational lifetimes compared to conventional Pt/C systems. In metal free and hybrid designs, N-G has also shown competitive activity and stability in both acidic and alkaline environments. Despite these advances, challenges remain regarding the precise identification of active nitrogen configurations, long term durability under harsh conditions, and scalable synthesis routes. Addressing these issues through controlled doping, defect engineering, and improved composite architectures will be essential to fully exploit the potential of N-G in sustainable, high efficiency fuel cell systems.