The crystallization process of Se87.5 Te10 Sn2.5 glassy was studied by differential thermal analysis (DTA) technique under non-isothermal condition at various heating rates. The crystallization parameters were calculated using different models. The validity of the Johnson–Mehl–Avrami (JMA) model to describe the crystallization process for the studied composition was discussed. Results obtained by directly fitting the experimental DTA data to the calculated DTA curves indicate that the crystallization process of Se87.5 Te10 Sn2.5 glass cannot be satisfactorily described by the JMA model. On the other hand, kinetic parameters of both the peak crystallization temperature Tp and the glass transition temperature Tg are significantly influenced by the heating rate. Simulation results indicate that the Sestak–Berggren (SB) model is more suitable to describe the crystallization kinetics. The crystalline phases were identified by using X-ray diffraction technique (XRD) and scanning electron microscopy (SEM).