This study aimed to determine the characteristics of Hibiscus sabdariffa as a fiber-reinforcement material for denture acrylic resins. The Hibiscus sabdariffa fiber was extracted by hot water retting. The fiber was treated at room temperature in aqueous solution of NaOH for 8 hours at 8% concentration. Micrometre gauge and Field emission scanning electron microscope (FE-SEM), Archimedes principle, Fourier transform infrared (FTIR) spectroscopy, and Thermogravimetric analyser were used to characterize the diameter, morphology, density, water content and absorption, functional chemical component and thermal behaviour of Hibiscus sabdariffa fiber. In addition, the reinforcing characteristics of Hibiscus sabdariffa fiber was evaluated using denture acrylic resin. The flexural strength was measured in line with ASTM D 790 using Lloyd TM three point bending machine. In line with ASTM D 256, the impact strength was measured using Hounsfield TM charpy tester. The Micrometre gauge and FE-SEM analysis confirmed that diameter of Hibiscus sabdariffa fiber is within the range of other established reinforcing lignocellulosic fibers so also are the density, moisture content and absorption. The FTIR spectroscopy and TGA analysis confirmed the presence of cellulose, hemicellulose and other components in the fiber which were modified by treatment resulting in decreased hydrophilicity of the fibers thereby improving the thermal stability of the fiber. Furthermore, the bond fiber/matrix adhesion was improved which resulted in improve mechanical properties of the composite. The salient features of this study indicated that based on the suitable properties, Hibiscus sabdariffa fiber can be applied to reinforcing denture acrylics. In addition, and potentially, the use of Hibiscus sabdariffa fiber in reinforcement of denture acrylic resins can trigger further economic benefit while ensuring sustainable, green and safer environment.