Trapping centers in as-grown GaSe single crystals have been investigated by thermoluminescence (TL) measurements in the temperature range of 30-300 K. The analysis of the observed peaks in TL glow curve to determine the activation energies of the associated centers were accomplished using curve fitting, initial rise and peak shape methods. Activation energies of the revealed four trapping centers obtained from various methods were in good agreement with each other on the energy values of 0.14, 0.18, 0.24 and 037 eV. The annealing effect on the TL properties of the GaSe single crystals was also studied for the annealing temperature of 500 degrees C. It was observed that annealing significantly decreased the U intensity and shifted the observed peaks to lower temperature resulting with smaller activation energy values. The distribution of the trapping centers with most intensive peak was also studied on both as-grown and annealed crystals. (C) 2014 Elsevier B.V. All rights reserved.