Fibers and foams are commonly used in commercial solutions in acoustic applications because of their excellent sound absorption coefficient at high frequencies [1, 2]. The present study focuses on improving the sound absorption property of lightweight concrete by adding coconut fibers in different proportions (0.5%, 1%, and 1.5%) in concrete where fine aggregate is replaced by 7% perlite. Gypsum is added to replace 10% cement to make the concrete lightweight and also to perform as a good sound absorber. A foaming agent is also added to improve the porous property of the concrete [2]. The acoustic absorption coefficient is determined using the impedance tube method-ISO 10534- 1:1996 [7]. The responses from the tests performed are compared and the results are analyzed. The results show that the addition of fiber increases sound absorption property and also the addition of perlite and gypsum which makes the concrete lightweight also has a significant impact.