Graphdiyne (GDY) has gained recognition as an effective base for electrocatalytic systems owing to its distinctive sp–sp2 carbon structure, expansive surface, and superior electrical conductivity. This review examines how GDY-supported catalysts boost the efficiency of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Combining GDY with transition metal oxides (e.g., NiFe2O4, Co3O4, MnO2), single-atom catalysts (e.g., Ru, Ir, Fe), and bifunctional systems (e.g., CoFe-GDY, Ni-GDY) enhances stability and charge movement, elevating catalytic performance. Additionally, hybrid materials integrating GDY with MXenes, metal–organic frameworks (MOFs), and perovskites show improved electrocatalytic effectiveness, durability, and potential for large-scale use. The discussion covers recent synthesis advancements, obstacles in mass production, and future opportunities for refining GDY-based catalysts in green energy technologies.