Abstract Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269±0.006 ms, was observed from uranyl in 1 M HF+1 M HClO4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO2F2. Studies on the effect of added LiNO3 or Na2WO4·2H2O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF6 content of WF6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF6.