Due to the need for strong and lightweight materials that can operate at much higher temperatures than those of conventional metals and alloys, there has been a significant development of advanced composite materials in recent years. Ceramics and ceramic-matrix composites are playing an increasingly important role in this area. In order to use these materials efficiently, their mechanical properties must be known: stiffness and damping are two of the most useful material properties. The objective of this paper is to report the measurements of the damping and dynamic elastic modulus of certain ceramics and ceramic-matrix composites at elevated temperatures. The materials that have been studied are fused quartz, recrystallized alumina, a carbon glass lamellar composite, and reaction-bonded silicon carbide. The Piezoelectric Ultrasonic Composite Oscillator Technique (PUCOT), suitably modified for elevated-temperature measurements, was used to determine these properties. Measurements were done in the frequency range of 40 to 80 kHz and the temperature range of 21 to 600°C.