Thermoluminescence (TL) characteristics of PbO-Al2O3-SiO2:Ho3+ glass system mixed with different concentrations of Al2O3 were studied in the temperature range 0–300°C. The samples were exposed to γ-rays in the dose range of 0 –5 kGy. The glow curves of the samples exposed >1.0 kGy, exhibited a dosimetric peak at about 209°C. With the increase of the dose up to 5 kGy, the TL light output increased considerably, and the peak was shifted towards higher temperature. A linear dose-dependent enhancement of the TL emission was also found for the glasses mixed with 5 and 8 mol% Al2O3. However, the glass mixed with 10 mol% Al2O3 exhibited supralinearity beyond 3 kGy. The mechanisms responsible for TL emission and enhancement of TL output were discussed in view of the results obtained from optical absorption, IR, and Raman spectral studies. The results suggested that both e- and h+ trapped centers were generated at the deeper trap levels and gave TL emission at higher temperatures. In the dose range of 2–5 kGy, the dose –response was found to be linear and could be useful for dosimetry in commercial radiation processing of perishable food commodities.