Tm(3+)-Yb(3+) codoped transparent oxyfluoride glass ceramics containing LaF(3) nanocrystals were obtained by thermal treatment on the as-made glasses. The formation of LaF(3) nanocrystals and the incorporation of Tm(3+) and Yb(3+) into LaF(3) nanocrystal lattice were confirmed by X-ray diffraction and high resolution transmission electron microscopy. Infrared quantum cutting involving Yb(3+) 950-1100 nm ((2)F(5/2)--> (2)F(7/2)) emission was achieved upon the excitation of the (1)G(4) energy level of Tm(3+) at 468 nm. We measured the photoluminescence properties of these glass ceramics. We also investigated the thermal treatment duration dependent quantum efficiency, and found that the quantum efficiency is 13% increased for the 0.5Tm(3+)-4Yb(3+) doped glass ceramic with a maximum value of 144%, and 16% increased for the 0.5Tm3+-8Yb3+ doped glass ceramic with a maximum value of 162%, respectively.