The effect of Sb at% on different temperature ranges dc-electrical conductivity are reported for thermally evaporated Se85−xTe15Sbx(x = 2.5, 5 and 7.5 at.%) glassy thin films. The structure and surface morphology of the considered samples were studied by the X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM) measurements. The electrical conduction in the Se85−xTe15Sbx chalcogenide glass system was found to be determined by different conduction mechanisms with different activation energy values at various temperature ranges. The relation between various structural parameters and the electrical activation energies was investigated. The analysis of the high-temperature conductivity data identified that the conduction mechanism on the basis of thermionic emission occurs over the grain boundaries according to Seto's model. In the amorphous to crystalline phase transition region, a model has been modified to describe the conduction mechanism. The modification is considering the percolation effects alongside with the effect of thermally activated electrical conductivity of the formed crystalline grains embedded in the sample amorphous matrix. The calculated electrical conductivity was found to be effectively fitted to the temperature-dependent electrical conductivity measurements for thermally evaporated Se85−xTe15Sbx films and showed promising candidates to be examined in different chalcogenide systems .