Cubic monodisperse BaCeF₅ and BaCeF₅:Tb³⁺ nanocrystals have been successfully synthesized by a citric acid assisted solvothermal method. The crystalline phase, size, morphology, and luminescence properties were characterized using powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescent excitation spectra (PLE) as well as dynamics decay. The results reveal that the Tb³⁺-doped BaCeF₅ sample shows a strong green emission centered at 546 nm, corresponding to the ⁵D₄→⁷F₅ transition of Tb³⁺ due to an efficient energy transfer from Ce³⁺ to Tb³⁺. The decay lifetime of Ce³⁺ monotonically increases with increase of Tb³⁺ concentration. The critical energy transfer distance between Ce³⁺ and Tb³⁺ was also calculated by methods of concentration quenching and spectral overlapping. Experimental analysis and theoretical calculations reveal that the dipole–dipole interaction should be the dominant mechanism for the Ce³⁺–Tb³⁺ energy transfer.