Atomic scale simulations were used to predict defect formation in tetragonal ZrO2 doped with Cu and Sb. Both dopants form strong associations with oxygen vacancies impeding oxygen progression through the oxide. Sb suppresses the free oxygen vacancy population though Cu increases the concentration. Thus, while the addition of Sb is predicted to be beneficial against corrosion, Cu will show a more complex behavior. Previous simulations showed that Ni0 promotes molecular hydrogen dissociation. Neither Cu nor Sb exhibit this behavior despite Cu+ having the same electronic configuration as Ni0. Both Cu and Sb show a favorable response to applied local space charges.