Mesoporous NiO/NiFe₂O₄ multi-composite hollow nanocages via monodisperse Ni₃[Fe(CN)₆]₂ prussian blue analogue nanocube precursors were successfully synthesized. The three-dimensional (3D) mesoporous and hollow structures provided an efficient electrolyte diffusion path and a high surface area, resulting in the enhancement of electrocatalytic activities for the oxygen evolution reaction. The overpotential and Tafel slope of mesoporous NiO/NiFe₂O₄ multi-composite hollow nanocages were as low as 303 mV at a current density of 10 mA cm⁻² and 58.5 mV dec⁻¹, respectively. In addition, the composite showed excellent durability at approximately 60 mA cm⁻² for 12 h.