GdTiO3 is a prototypical Mott-insulating perovskite that exhibits a rich interplay between spin, orbital, and lattice degrees of freedom. Here we report a systematic study of the magnetic anisotropy of high-quality GdTiO3 single crystal grown by the optical floating-zone technique. Comprehensive magnetization measurements performed with a vibrating-sample magnetometer (5K ≤ T ≤ 70K, |µ0H| ≤ 9T) reveal a pronounced magnetic anisotropy. The ordering temperature is isotropic (TN ≈ 32K), but both the magnetic susceptibility and the spin-flop fields depend strongly on the direction of the applied field (H ∥ a,b,c). For each crystallographic orientation three distinct magnetic regimes are identified: ferromagnetic-like low-field phase, ferrimagnetic high-field phase and paramagnetic phase. These findings provide a solid experimental benchmark for theoretical treatments of spin-orbit coupling and anisotropic exchange in rare-earth titanates. Moreover, the sizable magnetic entropy change associated with the field-driven transitions suggests that GdTiO3 could be exploited in solid-state cryogenic refrigeration based on the magnetocaloric effect, offering a potential route to more efficient hydrogen liquefaction.