<p>Organic solar cells (OSCs), as a novel photovoltaic technology, have garnered significant attention due to their unique advantages, such as lightweight, flexibility, and large-area solution processability. However, despite significant improvements in power conversion efficiency (PCE), the long-term stability of OSCs remains a critical bottleneck hindering commercialization. In this context, Giant molecule acceptors (GMAs) have emerged as a promising class of non-fullerene acceptors. They are formed by precisely linking several (typically 2–8) high-performance monomer units through covalent bonds to form medium molecular weight molecules with definite structures and controlled molecular weights, effectively combining the high efficiency of small molecule acceptors (SMAs) and the superior stability of polymerized small-molecule acceptors (PSMA), showing great potential for developing highly efficient and stable OSCs. Currently, GMAs-based OSCs have achieved a PCE approaching 20% alongside excellent stability, exhibiting a <i>T</i>₈₀ lifetime exceeding 1000 h under 1-sun illumination. This progress highlights the great potential of GMAs in synergistically optimizing both the efficiency and long-term stability of OSCs, paving new avenues for their commercial applications. In this review, the potential of GMAs in fabricating efficient and stable OSCs is first discussed from the aspects of their structural characteristics, optoelectronic properties, aggregate morphology, and stability mechanisms. Subsequently, recent advances in high-performance and stable OSCs based on GMAs are systematically summarized, categorized by functionalization sites of the monomer units, with analyses of molecular design strategies and performance optimization mechanisms. Finally, the review addresses current challenges and shares perspectives on future research directions to advance the commercialization of this field.</p>