Abstract: Fiber reinforced thermoset plastic composites with a glass transition temperature of greater than 500° C. are disclosed. Certain embodiments of the disclosed fiber reinforced thermoset plastic composites are produced using pre-ceramic resin and fibers that are stable under thermal stress. Also disclosed are methods of making these fiber reinforced thermoset plastic composites. These methods include infiltrating thermally stable fibrous material with a pre-ceramic resin and introducing crosslinking. The disclosed methods produce a non-ceramic highly crosslinked thermoset plastic composite that possesses both thermal stability and mechanical strength.