Due to a certified 25.2% high efficiency, low cost, and easy fabrication; perovskite solar cells (PSCs) are the focus of interest among the next-generation photovoltaic technologies. Long-term stability is one of the most challenging obstacles to bring technology from the lab to the market. In this review, applications of self-assembled monolayers (SAMs) to enhance the power conversion efficiency (PCE) and stability of PSCs is discussed. In the first part, the introduction of SAMs, and deposition techniques applied to different PSC architectures are described. In the middle section, current efforts to utilize SAMs to fine-tune the optoelectronic properties to enhance the PCE and stability are detailed. The improvements in surface morphology, energy band alignment, as well as reduced interfacial charge recombination induced by SAMs, and the trap passivation mechanism allowing optimal PCE and stability are described. A general outlook summarizing the importance of SAMs to the improvement of PSCs performance is also given, alongside a discussion of future opportunities and possible research directions.