The defects located at surface and grain boundaries are generally agreed to be the key factors limiting the power conversion efficiency and operational stability of the halide perovskite solar cells. Therefore, new techniques for surface and grain boundaries passivation are being continuously developed and studied. In this work, we investigate the impact of diffuse coplanar surface barrier discharge (DCSBD) nitrogen plasma treatment on the photoluminescence properties and performance of halide perovskite thin films in solar cells. We show that plasma exposure leads to an increase in photoluminescence, attributed to reduced defect densities, resulting in implied open‐circuit voltage improvement of up to 80 mV. Furthermore, solar cells fabricated with plasma‐treated layers exhibited open‐circuit gains up to 60 mV. These results demonstrate that, with careful optimization, DCSBD nitrogen plasma treatment is an effective method for enhancing the efficiency of perovskite solar cells. Moreover, it is an easily scalable and dry process, two factors that make it an ideal method for industrial applications.