Abstract MoSi 2-based composites possess significant potential to meet the demands of advanced high temperature structural applications in the range 1200–1600 °C, in oxidizing and aggressive environments. These materials constitute an important new class of “high temperature structural silicides”. The intermetallic compound MoSi 2 possesses properties which make it a very desirable matrix for high temperature composites, and these properties are described and compared with those of other high melting point silicides. The developmental history of composites based on MoSi 2 is traced from its beginnings to the present. Mechanical property improvements derived from SiC and ZrO 2 reinforcements, as well as matrix alloying, are described, and properties of current MoSi 2-based composites compared with those of silicon-based structural ceramics. Finally, important research and development directions for the continued improvement of MoSi 2-based composites and their use as high temperature structural components are discussed.