Large quantities of waste plastic and glass are generated annually in Iraq, while the continuous extraction of natural aggregates for road construction increases pressure on natural resources. This study investigates the combined use of locally sourced Iraqi river aggregate, waste glass and waste polyethylene terephthalate (WPET) in asphalt mixtures, an approach that has received limited attention in previous studies. River sand was used as the fine aggregate, while waste glass was used as a partial replacement of fine aggregate at replacement levels of 10%, 20% and 30% by weight. WPET was added 8% WPETto the asphalt binder using the wet process at contents of 4%, 8% and 12% by binder weight. Marshall stability, indirect tensile strength and tensile strength ratio tests were conducted to evaluate the mechanical performance and moisture susceptibility of the mix. Results showed that waste glass improved the Marshall stability up to an optimum replacement level of 20%, before declining at higher replacement levels. Similarly, 8% WPET produced the optimum performance by increasing stability, indirect tensile strength and moisture resistance, whereas increasing the content to 12% reduced the mechanical performance of the mixture. Overall, the combined use of 20% waste glass and 8% WPET produced the optimum asphalt mixture, indicating that the proposed mixtures can enhance asphalt mixture performance. This approach offers a practical solution for constructing asphalt pavement in Iraq.