Advanced engineering ceramics and composites have applications in many areas including manufacture, transportation, energy generation, environmental clean-up and aerospace. However, the conditions in which these materials are required to operate, such as in Generation IV nuclear systems, leading edges for hypersonic vehicles, advanced propulsion systems, are becoming more and more challenging. High or ultrahigh temperatures are often combined with severe corrosion environments and exposure irradiation. To meet the challenges for applications in these extreme environments, a number of new materials as well as processing, joining and testing/characterization methods have been developed in recent years. This symposium will bring scientists, engineers and young students together to share the recent achievements on design, modeling and processing of novel engineering ceramics and composites, as well as testing the thermal and mechanical properties, oxidation resistance in extreme environments. Particular emphasis is placed on multiscale structural-property relationships, design of new compositions/composites and new applications.