The development of functionally gradient materials (FGMs) represents a significant milestone in materials science and engineering, offering tailored material properties that transcend conventional limitations. Ultrasonic additive manufacturing (UAM) is an emerging metal additive manufacturing technique that can facilitate precise control over material composition and microstructure at the micron scale and enable the real-time fabrication of complex FGM architectures. The present chapter discusses in detail the production of FGM through UAM. The ability of UAM to fabricate FGM by strategically varying composition and microstructure along predefined directions is analyzed, and the factors involved are reported. By controlling the various process parameters of the UAM solid-state deposition process, it is possible to achieve the required material gradients and tailored mechanical, thermal, and functional properties. Furthermore, the chapter explores the capability of UAM to fabricate hybrid composites, in which dissimilar materials are integrated to achieve synergistic property combinations. The multi-material deposition capabilities of UAM enable researchers to manufacture functional components with superior mechanical properties, thermal stability, and wear resistance.