AbstractElectrocatalytic nitrogen oxidation reaction (NOR) offers an efficient and sustainable approach for conversion of widespread nitrogen (N₂) into high‐value‐added nitrate (NO₃⁻) under mild conditions, representing a promising alternative to the traditional approach that involves harsh Haber–Bosch and Ostwald oxidation processes. Unfortunately, due to the weak absorption/activation of N₂ and the competitive oxygen evolution reaction, the kinetics of NOR process is extremely sluggish accompanied with low Faradaic efficiencies and NO₃⁻ yield rates. In this work, an oxygen‐vacancy‐enriched perovskite oxide with nonstoichiometric ratio of strontium and ruthenium (denoted as Sr_0.9RuO₃) was synthesized and explored as NOR electrocatalyst, which can exhibit a high Faradaic efficiency (38.6 %) with a high NO₃⁻ yield rate (17.9 μmol mg⁻¹ h⁻¹). The experimental results show that the amount of oxygen vacancies in Sr_0.9RuO₃ is greatly higher than that of SrRuO₃, following the same trend as their NOR performance. Theoretical simulations unravel that the presence of oxygen vacancies in the Sr_0.9RuO₃ can render a decreased thermodynamic barrier toward the oxidation of *N₂ to *N₂OH at the rate‐determining step, leading to its enhanced NOR performance.