Oxygen evolution reaction (OER) is an integral step in the water‐splitting process. Hence, to promote OER, efficient catalysts are required to lower the energy barriers at the electrode/electrolyte interface. Low‐cost and highly active catalysts are in great demand. Herein, a ternary metal oxide, CoCuMnOx, synthesized by a facile hydrothermal method is reported, which possesses excellent catalytic ability for OER in alkaline electrolytes. The nanoscale morphology of the catalyst with flower‐like nanostructures is instrumental in increasing the electrochemical surface area of the electrode. The presence of multivalent ions and the incorporation of copper greatly enhance the electrochemical properties of the catalysts. The catalysts typically demonstrate an overpotential value of 220 mV for achieving 10 mA cm−2 current density and a Tafel slope of 73 mV dec−1. The catalysts demonstrate good stability with minimal degradation in OER activity even after 20 h of chronopotentiometry test. For practical applications, this low‐cost material holds great potential.