AbstractIt is particularly significant to apply stable and low‐cost catalysts in electrochemical water oxidation. It has been reported that molybdenum carbides have exceptional water dissociation ability in thermal catalysis. However, its role in electrocatalytic water oxidation, in which water dissociation is the key initial step, has not yet been paid attention to. Herein, cobalt oxide (CoOx) nanoparticles, by an incipient‐wetness impregnation method, were successfully supported on the surface of nitrogen‐doped porous carbon homogeneously distributed ultrafine α‐MoC nanoparticles with nitrogen‐doped porous carbon (α‐MoC/NC) and worked as efficient electrocatalysts for water oxidation. By regulating the loading amounts of cobalt oxide and the calcination temperature, a series of mesoporous CoOx@α‐MoC/NC composites were obtained. The optimal electrocatalyst exhibited low oxygen evolution overpotential (10 mA cm−2, 410 mV) and an excellent anodic stability. Experimental results implied that the synergistic effect between cobalt oxide and α‐MoC/NC can facilitate water oxidation, with the latter having the ability to dissociate water molecules.