In recent years, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA)-based inverted perovskite solar cells (IPSCs) have gained tremendous attention due to their simple device structure, easy fabrication process, and suitability for roll-to-roll process for fabricating flexible devices. With the recent years’ rapid progress, PTAA-IPSCs have achieved higher efficiency than other IPSCs, revealing great potential for future applications. Among various strategies to enhance the performance of PTAA-IPSCs, interfacial engineering has been highlighted with comprehensive merits, including improving the wettability of PTAA, enhancing the crystallinity of perovskite, modifying energy levels, and reducing defect traps at interfaces for enhancing charge transfer and reducing nonradiative recombination. Although extensive review articles have been published on PSCs, little attention has been focused on interfacial engineering of PTAA-IPSCs. It is believed that it is of great importance to summarize the fruitful breakthroughs in recent years in this area and give some prospective. In this review, the development of PTAA-IPSCs is summarized, and then interfacial engineering processes on perovskite, PTAA, and electron transport layer is systematically discussed, respectively. In addition, current challenges associated with the rapid developments in the field of PTAA-IPSC have been pointed out and insightful outlooks for the future design and commercial development of PTAA-IPSCs have been provided.