The growing demand for sustainableCoconut sheath fiber alternativesPolymer to syntheticComposites fibersCharacterization has driven interest in natural fibersNatural fibers as reinforcing agents in polymer compositesPolymer composites. In this study, coconut sheath fiberCoconut sheath fiber (CBF) was employed as reinforcement in a polymerPolymer matrix, with volumetric fractions ranging from 10 to 30%. The fibers were extracted from coconut palm sheaths, and their orientation and distribution were considered during specimen preparation. The impact performance of the compositesComposites was evaluated through Izod impact testing (ASTM D256). The results revealed a nonlinear trend, with energy absorption increasing significantly up to 25% fiber content, followed by a decrease at 30%, likely due to processing-induced defects and poor fiber dispersion. These findings highlight the potential of CBF as a sustainable reinforcement, while also indicating the existence of an optimal fiber content for maximizing impact resistance.