<p>Stretchable polymer solar cells (S-PSCs) have recently achieved a landmark efficiency exceeding 15%, marking a critical step toward their integration into next-generation wearable, portable, and conformable energy systems. This review highlights the key strategies that enabled this breakthrough, including molecular design of stretchable photovoltaic polymers, rubber-toughening approaches to stabilize microstructures under strain, and the development of multifunctional interlayers and eletrodes that balance mechanical resilience with electronic performance. We summarize the major achievements that have propelled S-PSCs from early proof-of-concept devices with modest efficiency to state-of-the-art systems rivaling their rigid counterparts. Beyond the efficiency milestone, we discuss the unique advantages of S-PSCs, such as their ability to offer power output gains under extreme deformation, which is essential for advanced deployments. This strain-induced power output enhancement mechanism provides new pathways for high-performance wearable devices. Finally, we provide an outlook on emerging trends, remaining challenges, and application scenarios, underscoring the opportunities for S-PSCs to play a pivotal role in the future of flexible and wearable optoelectronics.</p>