Among the major challenges facing the modern era of technological and industrial advancements are pollution and exponentially growing energy consumption. Pollution continues to be a menace affecting different aspects of life such as health, productivity, and comfort. This paper focuses on the elimination or reduction of sound pollution in buildings using cement-based boards made from pretreated coconut coir and oil palm fibers obtained from agricultural residues. The study includes an account of the preparation of fiber cement boards made from Portland cement Type 1, limestone powder, water, sand, and pretreated coconut coir and oil palm fibers at 5, 10, 15, and 20% by weight of powder materials, respectively, and a high-range water reducer in order to make sure that the natural materials would be spread in an even way throughout the specimens. Sound insulation tests were performed as key indicators of the performance of the fiber cement boards. It was found that an increase in the proportion of natural materials resulted in fiber cement boards with decreased density, compressive strength, and flexural strength. Furthermore, in relation to both physical and mechanical performance, the boards incorporating coconut fibers were superior to those incorporating oil palm fibers. With an increased proportion of natural fibers, sound insulation performance tended to improve. The boards prepared with coconut coir and oil palm fibers in this study yielded acceptable physical and mechanical properties and showed promise in relation to providing insulative protection against sound.