Creep in pore‐free polycrystalline aluminum oxide has been studied as a function of temperature, grain size, and strain rate. The behavior may be described by&sgr;&agr;d2&egr;˙, wheredis the mean grain diameter. Deformation is not controlled by basal slip but by a diffusional creep process as described by Nabarro and Herring, [F. R. N. Nabarro,Conference on Strength of Solids(The Physical Society, London, 1948), p. 75; C. Herring, J. Appl. Phys.21, 437 (1950)].