The development of scintillators is of fundamental and industrial meaning for their diverse applications. Despite the great advance in scintillating mono-crystals, challenge remains to search for novel scintillating materials with low cost, large volume, and high efficiency. Here, Tb3+-doped glass ceramics (GC) with crystallized Lu6O5F8 nano-crystals were prepared and characterized as potential X-ray scintillators. Their structural, optical, and luminescent properties were explored systematically. After thermal treatment, X-ray excited luminescence (XEL) intensity from Lu6O5F8:Tb3+ GC is greatly increased and the relative intensity is about 64% of commercial BGO scintillator, benefiting from preferential enrichment of Tb3+ ions into Lu6O5F8 nano-crystals with low phonon energy. Moreover, unusual decay behaviors of Tb3+ emissions in GC sample are observed and discussed. Our results indicate that rare earth doped GC may offer a novel platform for designing and fabricating new scintillating materials in the future.