Thermoluminescence (TL) studies on PbO–Al₂O₃–SiO₂: Dy³⁺ glasses mixed with varying concentrations  (5–10 mol%) of Al₂O₃ exposed to c-rays of dose, 0–5.0 kGy, have been carried out. The glow curves of these glasses have exhibited a dosimetric peak at about 180°C and a high temperature peak at about 300 °C. The TL light output has been observed to increase with increasing Al₂O₃ and also with theγ-ray dose. Results of these studies (coupled with data on optical absorption, and IR spectroscopy) have been analyzed within a framework of induced structural changes in the glass network. Probable mechanisms responsible for TL emission have been identified and discussed. The dose response of these glass samples exhibited linear behavior within the dose range of 1.0–3.0 kGy and beyond that it exhibited near saturation.