<p>High-entropy materials, which integrate five or more metal species into single-phase crystal structures, have garnered significant interest across various fields. In this study, we synthesized a low-cost, non-noble metal-based electrocatalyst known as a high-entropy metal–organic framework (HEMOF) for the oxygen evolution reaction (OER). The HEMOF was prepared via a solution-phase method utilizing transition metals and exhibited a single-phase, thin-sheet structure. Five distinct metals—iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), and copper (Cu)—were uniformly dispersed within the framework, with concentrations ranging from 5 to 35 atomic percent. The HEMOF demonstrated a high surface area and exceptional OER performance, achieving a low overpotential of 305&#xa0;mV at 10&#xa0;mA&#xa0;cm⁻², a Tafel slope of 68.5&#xa0;mV dec⁻¹, and remarkable stability over 10&#xa0;h. These findings suggest that the HEMOF represents a straightforward and cost-effective alternative to noble-metal-based OER electrocatalysts, contributing to sustainable energy conversion and storage.</p> Graphical Abstract <p>A low-cost, non-noble metal-based electrocatalyst, high-entropy metal-organic framework(MOF@FeCoNiMnCu), was synthesized for oxygen evolution reaction, achieving a low overpotential of 319 mV at 10 mA cm⁻² and excellent stability for 10 h. This study demonstrates high-entropy metal-organic framework (HEMOF) as a promising alternative to noble-metal-based electrocatalysts for sustainable energy conversion and storage.</p> <p></p>