Abstract The reinforcement of structural elements and construction materials using natural fibers has gained popularity among researchers and industries due to environmental concerns and financial problems of synthetic fibers. The contribution of natural fibers as soil reinforcement elements enhances the shear strength properties as the stresses in the soil mobilize tensile resistance in the fibers. Despite the specific limitations of direct shear test, it is considered as one of the most commonly used techniques that gives the design engineers a quick measure of soil strength properties when a certain fine content exists in the soil mixture. Therefore, this study is intended to present the results of a series of large-scale direct shear tests on compaction characteristics and shear strength properties of kenaf fiber reinforced soil. A total number of 128 tests have been carried out to determine the compaction and shear strength characteristics of unreinforced and reinforced sand-clay mixtures. Subsequently, the influence of kenaf fiber reinforcement on the stress-displacement relationship, volume change, ductility and failure state of reinforced soil was evaluated. Based on the results, the addition of a certain amount of kenaf fiber to the sand-clay mixture enhances the mixture ductility, improves the shear strength parameters, and ultimately makes it an appropriate candidate to be used in construction projects such as pavement layers, slope protection, embankment, and building foundation.