As with most engineering materials, the failure of composite materials, no matter how complex, can be divided into three discrete arenas: improper design, improper manufacturing, and improper use of the end product. This article reviews the failure causes from a broad perspective, so that the composites designer, manufacturer, and user can readily see some of the more common issues associated with unique materials. It discusses the three discrete arenas of failure of composite materials: improper design, improper manufacturing, and improper use of the end product.