Organic–inorganic halide perovskite solar cells (OIHPSCs) offer a fantastic opportunity to harness solar energy in a low cost and efficient way. This ambition for commercialization has been greatly encouraged by the surge in device performance from 3.8% in 2009 to the state-of-the-art 22.7%. For high device performance, tailoring the interfacial properties is demonstrated essentially important. Being in a molecular scale, the self-assembly monolayers (SAMs) are proved a facile but effective tool for interface modification. And lots of studies have demonstrated that SAMs have a variety of positive effects for perovskite solar cells, including mediating the morphology, improving energy level alignment, passivating trap states, etc. In this mini review, we give an insightful summary on the recent application of SAMs in OIHPSCs, analyze the mechanisms to improve device performance, and provide guidance to SAM-boosted perovskite solar cells for high performance and practical application. Finally, a landscape is depicted for future application of SAMs in perovskite solar cells.