<p>Hybrid organic–inorganic perovskites have attracted tremendous attention in recent years due to their outstanding optoelectronic properties, including strong light absorption, long carrier diffusion lengths, tunable bandgaps, and low-cost solution processability. These unique characteristics have enabled rapid progress in various optoelectronic technologies, particularly in Photovoltaics, light-emitting devices, and photodetection systems. Despite these advantages, the practical implementation of Hybrid Organic–Inorganic Perovskites remains significantly limited by their poor environmental and operational stability, especially under exposure to moisture, oxygen, heat, and prolonged illumination. To address these challenges, polymer–perovskite hybrid composites have emerged as an effective strategy for enhancing material stability while maintaining desirable electronic and optical properties. The incorporation of functional polymers can provide physical encapsulation, defect passivation, improved film morphology, and enhanced mechanical flexibility, thereby significantly improving device durability and performance. This review summarizes recent advances in the development of polymer–hybrid perovskite composites with a focus on synthesis strategies, stability enhancement mechanisms, and emerging device applications. Various fabrication approaches, including solution blending, in situ polymerization, polymer encapsulation, and nanostructured composite formation, are systematically discussed. Furthermore, the influence of polymer–perovskite interactions on charge transport, defect passivation, and environmental stability is critically analyzed. Finally, current challenges, including interfacial compatibility, scalable processing, and long-term operational reliability, are highlighted, and future perspectives for the design of next-generation polymer–perovskite composite materials are proposed.</p>