Abstract: An improved, fire-resistant, set gypsum composition contains set calcium sulfate dihydrate as the major ingredient and a reinforcing ingredient of resilient, flexible, boron-free glass fibers. Continuous filament forming glass compositions with a softening point preferably greater than about 1580° F. (about 860° C.) and more preferably greater than about 1681° F. (about 916° C.) may be used. The fibers typically are distributed as their separate constituent individual glass filaments uniformly throughout the set calcium sulfate dihydrate.