Efficiency and stability are the two most important factors in commercially scalable solar cells. In spite the high-power conversion efficiencies (PCE), the commercialization of perovskite solar cells (PSC) has been limited due to their low stability under ambient conditions. Environmental factors like moisture, heat, and light can all adversely affect PSC performance and limit device lifetime. In this review, we refer to the literature addressing the moisture induced stability issue of perovskite based solar cells. We present an overview on the moisture stability of the perovskite solar cells and clarify the effect of moisture on different layers in perovskite solar cells and the corresponding degradation process. Then we extend the discussion highlighting the strategies to prevent the moisture induced degradation in hybrid perovskite solar cells. The methods include composition engineering (cation and halide engineering) and interfacial layer engineering/surface passivation. We further summarize the utilization of doping techniques and use of organic/Inorganic passivators. We address methods of producing moisture stable 2D perovskites and admixtures of 2D and 3D perovskites. Lastly, the review highlights research directions focused on improving perovskite stability without compromising power conversion efficiency.