The purpose of this study is to develop epoxy composites with improved mechanical, thermal, and electrical properties. Semiconducting glass (SG) binary systems such as As2S3‐TlS and As2Se3‐TlS were synthesized in various mole ratios (1:1 and 1:3). Electrically conductive DGEBA‐type epoxy‐SG‐filled composites were developed containing 1–15 wt% of fillers and characterized by X‐ray diffraction and scanning electron microscopy techniques. As a result, the effects of the type and amount of semiconductive filler on the mechanical, thermal, and electrical properties of commercial epoxy resins (ERs) were examined. It was found that I2 doping of the filler significantly increased the electrical conductivity of the composites up to 10−3 S cm−1. Percolation concentrations were found to be 7 wt% for all composites studied. The maximum tensile strength changed in the range of 86–114 MPa was obtained with 5–10 wt% of SG particles. In addition, the thermal behavior and stability of the epoxy composites were studied using thermogravimetric analysis. The incorporation of SG particles increased the 10% decomposition temperature of neat epoxy by 5°C–35°C. ER/SG coatings showed the best adhesion results and perfect resistance to 3% NaCl, 3% HCl, and 5% NaOH solutions. POLYM. COMPOS., 39:681–690, 2018. © 2016 Society of Plastics Engineers