<p>The global transition toward net-zero emissions has positioned green hydrogen as a key element of sustainable energy strategies. Produced through water electrolysis powered by renewable energy sources, it offers a carbon-free energy carrier capable of decarbonizing hard-to-abate industrial sectors such as heavy industry and long-distance transportation. However, its widespread deployment remains constrained by the limited durability of conventional structural materials under the harsh electrochemical conditions of electrolytic cells, including corrosive environments, elevated temperatures, and sustained mechanical stress. High-entropy alloys (HEAs) have emerged as promising candidates owing to their multi-principal-element compositions, which confer exceptional mechanical strength, thermal stability, and corrosion resistance. This review examines the thermodynamic and electrochemical fundamentals of water electrolysis, discusses the material challenges faced by conventional alloys, and analyzes HEAs in the context of electrolytic cell components, with emphasis on corrosion resistance, hydrogen embrittlement, grain boundary engineering, and the minimization of reliance on critical raw materials and noble metals. The electrocatalytic potential of HEAs for hydrogen and oxygen evolution reactions is further explored through d-band theory, the Sabatier principle, and inter-elemental electronic interactions. Computational approaches, including CALPHAD modeling and machine learning-assisted screening, are highlighted as key enablers for rational HEA design. Collectively, this work establishes a framework for advancing HEA-based electrolytic systems that simultaneously address durability, efficiency, and cost constraints in green hydrogen production.</p>