<p>Dy³⁺ ion-doped MgGa₂O₄ phosphors were synthesized using a sol–gel method. A spinel structure of MgGa₂O₄ was obtained, but a secondary phase was observed as the content of Dy³⁺ ions increased. The emission spectra consisted of two emission peaks for the F_9/2 → ⁶H_15/2 (blue light) and the F_9/2 → ⁶H_13/2 (yellow light) electronic transitions of the Dy³⁺ ion itself. The lattice distortion caused by the difference between the Mg²⁺ ion and Dy³⁺ ion radius led to a change in the luminous intensity for the ⁴F_9/2 → ⁶H_13/2 electronic transition. The CIE (Commission Internationale de l'Éclairage [International Commission on Illumination]) chromaticity coordinates gradually shifted from the deep blue region to the near-white light region and from the light blue region to the white light region under excitation of 260&#xa0;nm and 357&#xa0;nm, respectively. The critical distance was found to be 13.955&#xa0;Å and 13.132&#xa0;Å for 260&#xa0;nm and 357&#xa0;nm excitation, respectively, indicating that the primary interaction mechanism between Dy³⁺ ions is dipole–quadrupole interaction within multipolar interactions. When the Dy³⁺ ion concentration was 12&#xa0;mol.%, the CIE chromaticity coordinates were <i>x</i> = 0.34, <i>y</i> = 0.33, which is quite close to the NTSC (National Television System Committee) standard white light chromaticity <i>x</i> = 0.33, <i>y</i> = 0.33.</p>