In contrast to the mainstream research on molecular refrigerants that seeks magnetically isotropic molecules, we show that the magnetic anisotropy of dysprosium acetate tetrahydrate, [{Dy(OAc)3(H2O)2}2]⋅4 H2O (1), can be efficiently used for cooling below liquid‐helium temperature. This is attained by rotating aligned single‐crystal samples in a constant applied magnetic field. The envisioned advantages are fast cooling cycles and potentially compact refrigerators.