Halide perovskites quickly overrun research activities in new materials for cost-effective and high-efficiency photovoltaic technologies. Since the first demonstration from Kojima and co-workers in 2007, several perovskite-based solar cells have been reported and certified with rapidly improving power conversion efficiency, now approaching the theoretical limit. Recent reports demonstrated that perovskites outperform the most efficient photovoltaic materials to date. At the same time, they still allow solution processing as a potential advantage in delivering a cost-effective solar technology. The most stable and efficient perovskites contain lead, among the most toxic elements on earth. Lead-free alternatives have been reported with impressive progress in power conversion efficiency for tin-based (lead-free) perovskites. However, the stability of tin-based perovskite solar cells is still unexplored. In the present talk, we will focus on the stability of tin-based (lead-free) perovskite solar cells.