This article describes the role of mechanical stresses in the high temperature oxidation of metallic materials. These stresses may result from oxide scale growth, surface curvature or edges, temperature variation, or from external forces. The different modes of scale failure are discussed and model equations are given quantifying the failure strains. Furthermore, measurement techniques are presented which allow the experimental determination of oxide scale failure strains. In addition, emphasis is placed on the healing behavior of oxide scales after mechanical failure while maintaining the protective effect of scales even after cracking or spalling. The protective effect is, however, limited by subsurface zone depletion in the metal, deteriorating the healing capacity of the alloy.