The room temperature thermoluminescence (RTL) decay from γ-irradiated LiF single crystal (Harshaw), NaF and KF powders (40–60 mesh) were studied as a function of the gamma radiation dose. The total luminescence reaches a maximum for a particular dose depending on the nature of the crystal. The emission spectra for LiF, NaF and KF showed one, two and three emission bands, respectively, in the range 375 to 700 nm. The RTL disappears at higher doses for these fluorides. The results are explained on the basis of postulated metastable energy level.