Glass as a cover material for solar energy harvesting constitutes a significant part of the cost. Furthermore, is glass an important component for efficient light capture and protection to the environment. Research and development of cover glass is needed to increase the service lifetime and to reduce the cost per watt peak. Recent research efforts have provided knowledge of which properties that needs to be optimized balancing efficiency, service lifetime and cost. Challenges with the development of cover glass for efficient harvesting of solar energy will be discussed. Some recent results related to optimization of the glass composition for enhancing properties for the purpose and the deposition of functional thin films will be presented. The failure modes for PV modules and how glass can improve the resistance to failure will be discussed. Developments of transparent and robust multifunctional coatings that provide anti-reflective and anti-soiling properties on the outer glass surface are desired. On the interior surface are anti-reflective and chemical barrier multifunctional coatings desirable to increase transmission and reducing potential induced degradation (PID). Replacing the conventional silver strings in PV modules with transparent conductive materials and back-reflecting backsheet materials are among the promising techniques for further maximizing the efficiency.