The oxygen evolution reaction (OER) is of great importance for renewable energy conversion and storage; however, the intrinsic process is sluggish and suffers from severe efficiency loss as well as large overpotentials. In this work, with the introduction of the plasmonic effects by design of the Au‐MnO2 hybrid catalysts, it is demonstrated that this photophysical phenomenon could largely promote the confinement of the outer electrons of Mn cations by plasmonic “hot holes” generated on gold surface. These “hot holes” work as the effective electron trapper to form the active Mnn+ species which could provide active sites to extract electrons from OH− and eventually facilitate the electrochemical OER catalysis under low laser power. By tuning the laser intensity from 100 to 200 mW, the overpotential is decreased from 0.38 to 0.32 V, which is comparable to IrO2 and RuO2 catalysts. These findings may provide insights into activation of plasmon‐promoted electrocatalysis under low power laser irradiation/treatment and the design of novel composite electrocatalysts. A plasmon‐promoted electrochemical catalyst for oxygen evolution reaction (OER) is developed by integrating gold nanoantennas with MnO2 nanosheets. This work provides new insights into understanding light‐promoted electrochemical OER catalysis and sheds light on developing new plasmonic electrocatalysts under low power laser or sunlight irradiation.