The solar radiation absorbed by photovoltaic panels is not fully utilized in the production of electricity. When the photovoltaic panels are exposed to solar radiation, part of the energy of the incident radiation is transformed into heat accumulated inside these panels. The heat accumulated inside the photovoltaic panels causes two types of losses. The first type of losses is the increase in the operating temperature of the panels and the deterioration of their efficiency and life span. The second type of losses explains that part of the energy of the incident radiation is transformed into heat inside the panels and does not contribute to the production of electrical energy. There are several cooling systems that have been applied to photovoltaic panels for the purpose of regulating their temperature including air, water, and nanofluid cooling systems, which are mostly done by placing a solar collector in the back side of the photovoltaic panels (PV/T). There is also a recently used system that uses phase change material (PCM) in cooling. This paper provides a comprehensive review of several cooling methods and their improvements that researchers have focused on. Through this review, it is clear that the best improvement in the performance of the photovoltaic panel occurs when using PCM because of the high heat transfer coefficient of these materials. Performance improves more when the addition of nanoparticles to the phase change material (PCM-Np) and also when merging (PCM) with (PV/T).