Perovskite solar cells (PSCs) have attracted global attention due to their remarkable efficiency gains, increasing from 3.8% in 2009 to 26% today, driven by the exceptional properties of perovskite materials such as excellent light absorption, high charge-carrier mobility, and long lifetimes. Metal halide perovskites, including methyl ammonium lead iodide, offer the potential for low-cost, scalable solar technologies. However, the primary challenge lies in their instability and degradation, particularly under moisture and environmental exposure, limiting their operational lifespan to well below the 10-year requirement for commercial viability. The soft, ionic nature of perovskite materials complicates efforts to enhance long-term stability. Current research focuses on structural modifications, advanced charge transport materials, and improved encapsulation techniques to address these challenges. This chapter examines key factors influencing PSC stability, highlights recent advancements, and explores future directions, emphasizing encapsulation’s pivotal role in achieving durable and commercially viable devices while inspiring further innovation in this transformative field.