Cooperative upconversion in Tb3+/Yb3+-codoped SiO2-BaF2-ZnF2 oxyfluoride glasses under 980 nm laser excitation was reported. For comparison, fluorescence emissions of Tb3+/Yb3+-codoped glasses were also measured. Both D-5(4)-> F-7(J) (J=6, 5, 4, 3) and D-5(3), (5)G(6) -> F-7(J) (J=6, 5, 4) transitions of Tb3+ are observed in upconversion and fluorescence spectra. The effect of Tb3+ and Yb3+ concentration, and temperature on upconversion luminescence was investigated. The dependence of upconversion emission intensity on pump power was measured and the upconversion processes including cooperative energy transfer were discussed in detail. (C) 2017 Elsevier Ltd. All rights reserved.