A hydrogeomechanical numerical model is presented to evaluate three-dimensional groundwater flow and land deformation in unsaturated true anisotropic aquifers due to groundwater pumping. This multidimensional numerical model is developed on the basis of the fully coupled poroelastic governing equations for saturated-unsaturated groundwater flow in deforming true anisotropic geologic media and the Galerkin finite element method. A series of true anisotropic aquifers, which comprise variously tilting layers, respectively, and a corresponding isotropic aquifer, which is composed of a geometrically averaged equivalent isotropic material, are simulated for the purpose of comparison. The numerical simulation results show that true anisotropy has significant effects on the spatial distributions and temporal changes of hydraulic head and displacement vector. Such effects of true anisotropy are caused by the uneven partitioning of the hydraulic pumping stress between the vertical and horizontal directions in both groundwater flow and solid skeleton deformation fields. This directionally uneven partitioning of the hydraulic pumping stress results from both the differences in hydraulic and mechanical properties among the principal axes and the discordance between the global coordinate axes and the principal axes.