Thermoluminescent properties are reported here on γ-irradiated α-Al2O3 and ruby single crystals, before and after the specimens were subjected to hydrostatic pressures of 24 kbar for 255 min at 773°K and at 30 and 40 kbar for 30-min periods at room temperature. Glow-curve changes and peak resolutions occur for white sapphire in the temperature range of 340 to 623°K. The graphs show regularity with regard to glow-peak temperatures and their sensitivity to higher annealing temperatures after pressure. A single pressure-sensitive peak at ~503°K appears in ruby after applying pressure or after γ irradiation. Activation energies for several peaks as calculated from the results are also given.