This paper aims to determine the macroscopic thermal conductivity coefficient of Lightweight Expanded Polystyrene Concrete (LEPS-C) using the homogenization approach through analytical calculations. The influence of expanded polystyrene on the overall thermal conductivity coefficient of LEPS-C was determined using classical homogenization models based on the solution of the Eshelby problem, with the matrix phase being concrete and the inclusion phase being expanded polystyrene particles randomly distributed in the matrix phase. The content of substituted expanded polystyrene particles was varied from 0% to 40% by volume of concrete. The analytical calculation results obtained from the homogenization models were compared with the experimental results, showing good agreement and demonstrating the efficacy of the homogenization method in predicting the macroscopic thermal conductivity of LEPS-C.