The peak toughness of a commercial magnesia‐partially‐stabilized zirconia was strongly dependent on a postprocessing, postspecimen preparation, and modest annealing (1000°C for 20 min), increasing it from ∼9 to almost ∼18 MP a·m1/2. Further study of this surprising phenomenon revealed that increases in toughness occurred for annealing temperatures as low as 275°C. The low toughness of the as‐received materials is due to a post‐manufacture room‐t