Introducing oxygen vacancy into the transition metal oxide materials has become an effective strategy to boost its electrochemical performance. Herein, a series of identical oxygen-vacancy-rich bismuth oxybromide (BiOBr) nanosheets are rationally prepared via a facile hydrogenation process. Electrochemical data show that reduced BiOBr nanosheets electrodes containing appropriate oxygen vacancies exhibit a significant improvement on capacitive performance compared to the pristine electrodes. The as-prepared BiOBr100 electrodes exhibit much higher specific capacitance (689 F g−1 at 0.5 A g−1), as well as moderate cycling stability. Furthermore, the introduction of oxygen vacancies in BiOBr nanosheets can increase its conductivity. These findings demonstrate that appropriate introduction of oxygen vacancies can be an efficient strategy for enhancing the electrochemical performance of BiOBr nanosheets.