Lanthanum pyrosilicate La2Si2O7 (LaPS) single crystals were successfully fabricated by the floating zone (FZ) method with Tb doping concentrations of 0.1, 0.5, 1.0, and 2.0% for scintillation and photoluminescence (PL) study. X-ray diffraction patterns of the samples indicate a single phase of LaPS from their consistency with the reference pattern. Tb-doped LaPS has multiple emissions from Tb3+ 4f–4f transitions including those at 380, 420, 440, 480, 540, 590, and 620 nm, as observed in both PL and X-ray-induced scintillation spectra with a PL quantum yield of up to 50.1%. The PL and scintillation decay time constants obtained were 2.64–3.26 and 1.54–2.00 ms, respectively. In 137Cs (662 keV) γ-ray pulse area spectra, the 1.0% Tb-doped LaPS had the highest scintillation light yield of 47700 ph/MeV. From all the results in this study, the optimum Tb doping concentration in LaPS single crystals is considered to be 1.0% for scintillator application.