The epoxidation of propylene to produce propylene oxide (PO) has a vital role in the industrial production of several commercial compounds and the synthesis of numerous intermediates, fine chemicals, and pharmaceuticals. However, the current PO production processes pose significant problems regarding the environment and economy. The direct photo-epoxidation of propylene using molecular oxygen (an ideal oxidant with active oxygen of 100 wt %) under light irradiation is a promising technology to produce PO. This process offers numerous advantages, including the use of simple technologies, low-cost methods, and environmental friendliness. Many efforts have focused on the design of new photocatalyst systems, optimizing the conditions for a photocatalytic reaction, and elucidating the mechanisms of photo-epoxidation. This review is expected to serve as a comprehensive background, providing researchers with insight into the recent developments regarding the direct photo-epoxidation of propylene.