The use of composite materials can provide significant advantages for military vehicles and weapons systems. Metal matrix composites (MMCs), as well as organic matrix composites (OMCs)/fiber reinforced plastics (FRPs), can impart reduced weight while providing improved properties such as strength and wear resistance. There is also a potential for lower manufacturing costs. However, the absence of well-documented data on these materials has been a roadblock to their more widespread use in Army systems. While some resources, such as Military Handbook 17 (MIL-17), can provide general information for the consideration of composites in military applications, additional data on performance, life cycle cost, manufacturability, and reliability must be gathered with respect to the specific end-use application in mind. This paper discusses the necessary considerations for replacing monolithic metal components with composite structures in U.S. Army vehicles and weapons systems.