The purpose of this paper is to present a new spectroscopic experimental technique to study the contributions of the different cross-relaxation mechanisms observed in Dy3+ doped TeO2-GeO2-ZnO glasses, based on the luminescence decay curves from 4F9/2 → 6H13/2 (at 573 nm) transition of Dy3+ ions under spatial and temporal simultaneous UV (6H15/2 → 6P7/2) and IR (6H15/2 → 6F3/2,6H15/2 → 6H7/2 and 6H15/2 → 6H9/2) excitations, for which the results are reported. The spectroscopic characterization was carried out through Raman, optical absorption, luminescence decay time profiles, and energy transfer as a function of Dy3+ ions content (0.5–5%). Emission spectra measurements indicated that concentration quenching is active in the samples. The lifetime decay of emission at 573 nm (4F9/2 level) was studied under excitation at 355 nm. At lower concentration of Dy3+, the temporal behavior of the emission at 573 nm is exponential, however, it becomes non-exponential as the concentration increases. The emission decay curves at 573 nm were fitted to Inokuti-Hirayama model and an energy transfer process dominated by an electric dipole-dipole interaction was deduced. A shortened lifetime was observed as the dysprosium ion content increased, which is attributed to non-radiative energy transfer between Dy3+ ions through the cross-relaxation mechanism. The analysis of the 4F9/2 → 6H13/2 (573 nm) emission decays, obtained under simultaneous excitation at 355 nm and at different infrared excitations 6H15/2 → 6F3/2 (905 nm), 6H15/2 → 6H7/2 (1100 nm) and 6H15/2 → 6H9/2 (1285 nm), allowed the determination of the dominant process in the cross-relaxation mechanism at high and low concentrations of Dy3+. It was possible to infer that in the glass with low concentration of Dy3+ the mechanism occurs predominantly by 4F9/2 + 6H15/2 → 6F11/2 + 6F3/2 channel, and for high concentration of Dy3+, the channels 4F 9/2 + 6H15/2 → 6F11/2 + 6F3/2, F9/2 + 6H15/2 → 6F5/2 + 6F9/2 +5H7/2, and 4F9/2 + 6H15/2 → 6F3/2 + 6F11/2 + 5H9/2 have a similar contribution to the Dy3+-Dy3+ resonant energy transfer. Display omitted