The use of vegetation for slope stability and reduced soil erosion is an area of growing interest, as it is believed that vegetation provides both mechanical and hydrological reinforcement to the soil. The present study focuses on the effect of orientation and dimensions of roots on the shear strength of root-reinforced Unsaturated soils. The soil used for the investigation was collected from Powai, Mumbai, and analysed using a direct shear test apparatus. Vetiver roots were chosen because of their stronger, longer, and denser root network system and also high potential to absorb moisture through the pore space with ease. The efficacy of root-reinforced soil is influenced by the tensile strength of the roots, while the reinforcing mechanism of roots is derived from anchorage provided by main and lateral root reinforcement. The results showed that the shear strength parameters are highly dependent on the orientation of roots in reinforced Unsaturated soil. In the case of horizontally oriented roots, the shear strength of reinforced soil was noted to be lower than that of unreinforced Unsaturated soil, while in the case of roots oriented vertically, reinforced soil showed a higher shear strength than that of unreinforced Unsaturated soil. Notably, the orientation and dimensions of roots, along with root morphology, have played a vital role in improving the shear strength of soils.