Learning is an ornament in prosperity, a refuge in adversity, and a provision in old age. ——Aristotle
La5-x-ySi2BO13:xCe3+, yTb3+ phosphors were synthesized by a solid-state reaction, and their luminescence properties have been investigated. The luminescent emission (PL) and excitation (PLE) spectra reveal that a broad absorption band between 200–400 nm is ascribed to the sensitizer of Ce3+, and the multiple emission bands are corresponding to the characteristic transitions of Ce3+ and Tb3+, respectively. On the basis of the analysis of the luminescence spectra, the energy transfer from Ce3+ to Tb3+ ions takes place in the La5-x-ySi2BO13:xCe3+, yTb3+ phosphor, which demonstrated to be a dipole-dipole mechanism. The energy transfer efficiency increases with increasing Ce3+ doping content. The critical distance Rc of Ce3+ to Tb3+ ions in La5Si2BO13 host was calculated to be 0.973 nm.