Metal halide perovskite (MHPs) solar cells represent a promising newcomer in the front of emerging photovoltaic technologies to address the dramatic energy crisis and climate change that we are facing. The exceptional properties of MHPs derive from their hybrid organic-inorganic nature, which allows also for low-cost and straightforward processing. Solar cells containing MHPs as absorbing layer have already achieved a power conversion efficiency of about 25,7 %, close to the efficiency of silicon-based devices. Nevertheless, a major limitation, still preventing the uptake of the technology, is related to the reduced stability of these materials when exposed to operative conditions, namely temperature, light, and moisture. Herein, an effective defect passivation of MHP surfaces is a key strategy to tackle both the stability and the enhancement of solar cell performances. Although many solution-based approaches ¹ have been tested, we propose here an innovative use of plasma, as a solvent-free, scalable, and non-invasive promising strategy to boost MHP solar cells performances ². As benchmark material we used Methylammonium Lead Iodide perovskite; thus we have exposed the surface of polycrystalline thin films made of this material to different plasma conditions implying the variation of power, gas, and treatment time, both for low-pressure (LP) and atmospheric pressure plasmas (APPs). The impact of Ar,  N₂, H₂ and O₂ LPPs on MAPbI₃ optochemical properties and morphology was correlated to the performance of the photovoltaic devices and rationalized by density functional theory calculations³. An interesting improvement in photoluminescence was observed for the Ar and H₂ treated films, while an improvement in PCE was observed only for the Ar treated device. This result was ascribed to the efficient removal of the superficial organic component, revealed through X-ray photoelectron spectroscopy (XPS), following suitable surface passivation by the electron transporting layer deposition. APP treatments, fed with He gas, were tested on the surface of MAPbI_3, too. A milder morphological modification than LPP treatments was observed in this case, but withstanding good surface passivation, as confirmed through the improved photoluminescence intensity, while the effect in terms of photovoltaic devices is still under investigations. Moreover, starting from these encouraging results, new plasma surface processes are now object of evaluation, such as the plasma-deposition of thiophene-like films and the study of LPP treatments applied to tin-based perovskite solar cells, approaches which already show the great versatility and potential of plasma-based techniques.