Although metal halide perovskites are increasingly popular for the next generation of efficient photovoltaic devices, the inevitable defects from the preparation process have become the notorious barrier to further improvement of performance, which increases non-radiative recombination and lowers the power conversion efficiency of solar cells. Surface passivation strategies have been affirmed as one of the most practical approaches to suppress these defects. Therefore, it is necessary to have a detailed review on the surface passivation to reveal the improvements of the devices. Herein, the mechanism and recent advances of surface passivation have been systematically summarized with respect to various passivation approaches, including the Lewis acid–base, the low-dimensional perovskite, inorganic molecules, and polymers. Finally, the review also offers the research trend and prospects of surface passivation.