GexSe50Te50−x (x = 5, 15, 20, 35 at.%) bulk glasses were synthesized by the melt quenching method. The amorphous nature of the investigated glasses was determined by X-ray diffraction. Results of differential scanning calorimetry (DSC) of the studied compositions under non-isothermal conditions were reported and discussed. The glass transition temperature (Tg), onset crystallization temperature (Tc), and crystallization peak temperature (Tp) were determined from DSC traces at different heating rates. It was found that the values of Tg, Tc, and Tp rely on both composition and heating rate. A double crystallization stages were observed in the DSC results. Various kinetics parameters such as the glass transition energy (Eg), crystallization activation energy (Ec), and rate constant (Kp) were calculated. The glass-forming ability of the studied compositions was discussed as function of the determined kinetics parameters.