This study examines the potential of using waste foundry sand (WFS) as a substitute for natural sand in making concrete paver blocks. Foundry sand is a by-product of metal casting industries, and its disposal is an environmental challenge. By incorporating WFS in various proportions (0, 5, 10, 20, and 30%), we evaluated its effects on the physical and mechanical properties of the paver blocks, such as compressive strength, tensile strength, and water absorption. Our findings indicate that WFS is finer and chemically different from natural river sand. The water absorption of the paver blocks with WFS was found to be between 4.3 and 4.6% by mass. Compressive strength tests revealed values between 50.2 and 55.2 MPa, while tensile strength ranged from 3.50 to 3.78 MPa. Although the control mix (100% natural sand) showed the highest strengths, optimal results were achieved with 5 and 10% WFS replacement. In conclusion, incorporating WFS up to 10% can produce paver blocks with comparable strength to those made with natural sand, offering a sustainable and effective use of industrial waste in construction. This approach not only mitigates environmental issues related to WFS disposal but also provides a cost-effective alternative for producing high-quality concrete products.