This paper highlights the utilization of friction stir processing (FSP) and its different variants like friction stir channeling, additive friction stir processing, etc., in manufacturing engineering parts with improved properties. FSP is derived from a solid-state welding technique, friction stir welding. This process stirs the material mechanically in the presence of frictional heating. Being solid-state processing techniques, FSP and its variants not only result in minimum thermal degradation of the materials but also are less energy intensive and hence environment-friendly. FSP has been used to improve the strength and ductility of metals. The preparation of surface composite is also an attractive application. It has already been successfully applied to a wide range of materials, including aluminum, magnesium, steel, and even composites. Critical findings from existing literature on these different applications of FSP have been summarized here with an aim to find the future research trend. With further research and development, FSP is expected to continue to evolve and find new applications in aerospace, automotive, and marine industries.