Implementation of resonant nanoparticles (NPs) for improving performance of organometal halide perovskites solar cells is highly prospective approach, because it is compatible with the solution processing techniques used for any organic materials. Previously, resonant metallic NPs have been incorporated into perovskite solar cells for better light absorption and charge separation. However, high inherent optical losses and high reactivity of noble metals with halides in perovskites are main limiting factors for this approach. Incidentally, low-loss and chemically inert resonant silicon NPs allow for light trapping and enhancement at nanoscale, being suitable for thin film photovoltaics. Here photocurrent and fill-factor (FF) enhancements in meso-superstructured perovskite solar cells, incorporating resonant silicon NPs between mesoporous TiO₂ transport and active layers, are demonstrated. This results in a boost of device efficiency up to 18.8% and FF up to 79%, being a record among the previously reported values on NPs incorporation into CH₃NH₃PbI₃ perovskite-based solar cells. Theoretical modeling and optical characterization reveal the significant role of Si NPs for increased light absorption in the active layer rather than for better charge separation. The proposed strategy is universal and can be applied in perovskite solar cells with various compositions, as well as in other optoelectronic devices.