<p>Perovskite solar cells (PSCs) have emerged as promising candidates for next-generation photovoltaic technologies, combining high power conversion efficiencies having potential for low-cost, scalable fabrication capabilities. However, their commercial advancement is significantly limited by interfacial instabilities, non-radiative recombination losses, and degradation mechanisms, particularly at the interfaces between the perovskite layer and charge transport materials. Interface engineering has thus become a focal point in PSC research, offering a powerful means to optimise device performance and longevity. This review critically examines the recent progress in interfacial design strategies aimed at enhancing both the efficiency and operational stability of PSCs. Key approaches, including surface passivation, energy level tuning, the introduction of functional interlayers, and morphological control, are discussed in detail. Special emphasis is given on understanding the fundamental roles of interfacial energetics, defect dynamics, ion migration, and environmental sensitivity. Furthermore, the integration of two-dimensional materials, polymeric modifiers, and mixed-dimensional heterostructures is explored as a route to reinforce structural integrity and improve charge transport across interfaces. By consolidating insights from both experimental studies and theoretical modelling, this review highlights the pivotal role of interface engineering in addressing long-standing challenges and advancing PSCs towards commercial viability.</p>