It is important to determine the mechanical properties of reinforced soils, since they are extensively used in practice. In this study, laboratory triaxial tests and direct shear tests were carried out in order to determine the stress-strain and dilation characteristics of geotextile-reinforced river sand. The mechanical behaviour of the composite material was investigated through varying the type of geotextile and confining pressure. Interface properties of geotextile-reinforced samples were evaluated with the direct shear tests. The results demonstrated that geotextile inclusion increases the peak strength, and reduces dilation especially at higher confining pressures.