A transparent Er 3+ –Tm 3+ –Yb 3+ tri-doped oxyfluoride glass ceramics containing LiYF 4 nanocrystals were prepared. Under 980nm laser diode (LD) pumping, intensive red, green and blue upconversion (UC) was obtained. The blue, green, and red UC radiations correspond to the transitions 1 G 4 → 3 H 6 of Tm 3+ , 2 H 11/2 / 4 S 3/2 → 4 I 15/2 , and 4 F 9/2 → 4 I 15/2 of Er 3+ ions, respectively. This is similar to that in Tm 3+ –Yb 3+ and/or Er 3+ –Yb 3+ co-doped glass ceramics. However, the blue UC radiations of the Er 3+ –Yb 3+ co-doped glass ceramics is two-photon process due to cooperative energy transfer. The UC mechanisms were proposed based on spectral, kinetic, and pump power dependence analyses.