The rapid growth of the construction sector has intensified the demand for building materials, increasing pressure on natural resources and exacerbating environmental challenges. The clay brick industry, characterized by high energy consumption, faces significant prodution costs due to the elevated firing temperatures required, alongside environmental concerns such as substantial carbon emissions. The partial substitution of clay with ashes emerges as an eco-friendly solution to reduce excessive energy consumption and mitigate the environmental impacts of brick manufacturing while valorizing industrial waste. This study aims to enhance the energy efficiency of fired clay brick production by utilizing co-products from the olive industry, specifically Olive Pomace Combustion Fly Ash (OPCFA). A 3% OPCFA content was incorporated into the clay matrix, followed by controlled drying and firing cycles, with firing temperatures progressively reduced from 850 ℃ to 750 ℃. The reduction in firing temperature resulted in increased porosity and improved thermal insulation properties while maintaining mechanical performance within construction standards. These enhancements are attributed to the fluxing oxides in the ash, which facilitate vitrification at lower temperatures. Microstructural analyses, including scanning electron microscopy and nitrogen porosimetry, confirmed the influence of reduced firing temperatures on pore structure and material performance. The findings demonstrate that incorporating OPCFA not only lowers firing temperatures and energy consumption but also enhances the thermal and mechanical properties of the bricks. This approach offers a sustainable and practical pathway to advancing the environmental and economic sustainability of brick manufacturing.