Bio‐based waste from households and industries is a big problem for the world, however, turning it into valuable composite materials can offer a promising approach to deal with it. It involves the conversion of waste from different bio‐based sources such as cellulose waste from farming and forestry leftovers, chitin waste from seafood and mushrooms, and keratin waste from hair, nails, and feathers into natural fibers. These fibers are then effectively mixed with other materials to create composite materials having unique properties, such as high strength and stiffness, good thermal and electrical conductivity, and better barrier properties. Developing these materials is not just good for the environment because it reduces landfill waste and the reliance on non‐renewable resources, but it can also make economic sense for producers. In this review, the basic compounds of natural fibers and the development of composite materials from them are explored and discussed in detail. Furthermore, their chemical and mechanical properties are discussed and summarized. In the final section, a brief overview of the challenges and the future research needed in this fast‐evolving field is given.