Aluminum oxide fibers of the approximate percent composition by weight:______________________________________ Al.sub.2 O.sub.3 61-98% preferably 76-96% SiO.sub.2 1-20% preferably 3-15% P.sub.2 O.sub.5 0-10% preferably 0-5% B.sub.2 O.sub.3 0-10% preferably 0-5% MgO 0-5% preferably 0-1% C 0.1-4% preferably 0.5-2.8% ______________________________________ The fibers are produced by dry spinning a solution containing a neutral or basic aluminum salt of a monobasic lower carboxylic acid, a hydrolyzed silicic acid ester or organoalkoxysilane and polyethylene oxide having a degree of polymerization of at least about 2,000. The product is then heat treated at a temperature between about 400.degree. and 1,800.degree.C. Phosphorus, boron and magnesium may also be present in the solution and end up in the fiber as oxides.