Energy demand in the world is overgrowing due to rising population and technological developments. It is vital to move toward a reliable, economical, and sustainable renewable energy source for energy needs arising in the future. Among other renewable energy sources, solar energy is a promising source of energy for handling long-term problems in the energy crisis. Solar power generation is expanding globally due to high energy demands and decreasing fossil fuel reserves, which are currently the primary sources of power generation. Photovoltaic (PV) cells are employed in the field of solar power generation for the conversion of solar radiation into electricity. Multiple PV cells combine in series or parallel to form a PV module (PVM). They are operated under continually changing environmental conditions causing various faults. Typically, faults are classified into visual, electrical, and miscellaneous faults. These faults should be identified and corrected immediately so that the performance, lifetime, and reliability of PV modules remain unaffected. This paper focuses on the detailed study of the types and causes of various faults that occur in a PVM. Several methods discussed in literature for fault diagnosis of PVM are reviewed. Faults occurring in PVM are particularly highlighted and diagnosis methods to detect and classify faults accurately are elaborated. Recommendations for future research direction are provided based on the reviewed papers. © 2020 Taylor & Francis Group, LLC.