Abstract The shear modulus is a fundamental parameter for evaluating soil deformation and stiffness. It is influenced by various factors, including void ratio, confining pressure, soil type, and soil suction (or degree of saturation). Similar to the coefficient of permeability of unsaturated soils, the shear modulus of unsaturated soils can vary significantly with changes in soil suction. Numerous empirical models have been proposed to describe the shear modulus of unsaturated soils.