The absorption and fluorescence spectra of Dy3+‐doped La3Ga5SiO14 (LGS) crystals were measured and analyzed according to the Judd–Ofelt theory. When applied, the following spectral parameters have been obtained: phenomenological intensity parameters Ωt, Ω2 = 2.64 × 10−20 cm2, Ω4 = 1.39 × 10−20 cm2 and Ω6 = 0.63 × 10−20 cm2. These intensity parameters were used to predict radiative properties that included electronic line strengths, radiative transition probabilities AJ″,J′, the radiative lifetime τrad, the fluorescence branching ratios βJ″,J′. The value of absorption section σabs(λ), and the integrated emission cross sections σem(λ) were also calculated. The emission transition 4F9/2 → 6H13/2 provides potential applications of LGS:Dy crystal as a laser material.