Nickel‐based electrocatalysts are promising candidates for oxygen evolution reaction (OER) but suffer from high activation overpotentials. Herein, in situ structural reconstruction of V‐doped Ni2P pre‐catalyst to form highly active NiV oxyhydroxides for OER is reported, during which the partial dissolution of V creates a disordered Ni structure with an enlarged electrochemical surface area. Operando electrochemical impedance spectroscopy reveals that the synergistic interaction between the Ni hosts and the remaining V dopants can regulate the electronic structure of NiV oxyhydroxides, which leads to enhanced kinetics for the adsorption of *OH and deprotonation of *OOH intermediates. Raman spectroscopy and X‐ray absorption spectroscopy further demonstrate that the increased content of active β‐NiOOH phase with the disordered Ni active sites contributes to OER activity enhancement. Density functional theory calculations verify that the V dopants facilitate the generation of *O intermediates during OER, which is the rate‐determining step for realizing efficient O2 evolution. Optimization of these properties endows the NiV oxyhydroxide electrode with a low overpotential of 221 mV to deliver a current density of 10 mA cm−2 and excellent stability in the alkaline electrolyte. In situ electrochemical oxidation and etching of V‐doped Ni2P pre‐catalyst enables the formation of NiV oxyhydroxide electrocatalysts for highly efficient oxygen evolution reaction. The partial dissolution of V can create enlarged electrochemical surface areas, while the remaining V modulate the electronic structure and the adsorption energy of OER intermediates. The in situ reconstructed catalyst displays extraordinary catalytic performance and stability.