In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.