The present study reports the investigation of the structure, morphology, optical and electronic properties of the annealed thin films of the semiconducting Ge₁₀Se₇₅Ag₁₅ composition. The crystalline phases Ag₂Se, GeSe₂ and Se were found in the Ge₁₀Se₇₅Ag₁₅ thin films and their crystallites size, strain and the dislocation density were changed by the variation of the temperature. These results confirmed the occurrence of the amorphous-crystallization phase transition in Ge₁₀Se₇₅Ag₁₅ films. Many linear, nonlinear optical and electronic parameters were determined which also showed a variation with the temperature. The dependence of the refractive index on the electronic polarizability was examined. The band gap increased from 1.67 to 1.85 eV while the width of localized tail states decreased from 0.022 to 0.010 eV with the increasing the annealing temperature which indicates that the localized states have a role in controlling the band gap of the investigated films. The relation between the refractive index and band gap enabled us to get the values of the refractive index by different methods. Also from the present results we conclude that the annealing temperature has a role in tuning as well as optimizing the optical and electronic parameters of the fabricated films. The results were discussed in terms of different proposed models.