The high temperature isothermal oxidation behaviour of work rolls and the oxide structures resulting from this process are presented. Oxidation of these alloys at 615 °C under various environmental conditions resulted in the formation of oxide crystals of different morphologies, depending on the chemical composition of the alloys and the gases present in the oxidant atmosphere. Particularly, the surface oxidation of high speed steel and high chromium iron for work rolls in hot strip mills included the formation of whiskers, platelets, and crystallites. The composition of the oxidant atmosphere also influenced the oxidation rate of the specimens by promoting the formation of protective or non-protective oxides. The reasons for the development of the different oxide morphologies and the effect that the oxides formed on the surface exert on the behaviour of important tribological variables present in the hot rolling of steel such as friction are discussed.