Mechanical creep of scandia stabilized zirconia containing 10 mol% Sc2O3 was measured. The activation enthalpy is 4.4 eV, revealing that the creep process is cation-diffusion-controlled, and creep can be correlated to known cation-diffusion coefficients. In particular, the creep exponent is 2, meaning that it is grain-boundary sliding controlling the creep process. (C) 2008 Elsevier B.V All rights reserved.