The escalating demand for sustainable hydrogen production has driven the exploration of biomass-derived carbon materials as cost-effective and eco-friendly alternatives to noble metal-based catalysts for water electrolysis. This review comprehensively examines recent advancements in synthesizing and optimizing biomass-derived carbon materials, including pyrolysis, hydrothermal carbonization, and microwave-assisted methods, alongside activation strategies such as physical, chemical, and templating techniques. These materials exhibit tunable porosity, heteroatom doping, and high surface area, enabling elevated catalytic performance toward both oxygen evolution (OER) and hydrogen evolution (HER) reactions. By integrating transition metals or heteroatoms (e.g., N, P, S), biomass-derived carbons achieve performance comparable to conventional Pt- or IrO2-based catalysts. Furthermore, bifunctional catalysts and hybrid electrolysis systems demonstrate synergistic efficiency, reducing overall energy consumption. Despite progress, challenges persist in pore structure regulation, conductivity enhancement, scalability, and long-term stability. This review underscores the potential of biomass-derived carbons to advance green hydrogen technologies while advocating for interdisciplinary efforts to address existing limitations and accelerate industrial adoption.