The energy levels of Dy³⁺ ions have been determined in lithium yttrium borate (Li₆Y(BO₃)₃) single crystals in a wide spectral range between 3000 and 40,000 cm⁻¹ using optical absorption and luminescence spectroscopy, which also allow for an analysis of the ground state. The crystal field splittings of the ⁶H_15/2 ground state and all excited states up to the ⁴F_7/2 manifold were obtained at a low temperature, based on luminescence (T = 4.2–78 K) and absorption (T = 8–100 K) measurements, respectively. The numbers of experimentally observed Stark sublevels are in agreement with those expected theoretically for Dy³⁺ ions occupying a single low symmetry (C₁) site.