Dy3+ and Ce3+ emission in NaMg(SO4)F phosphor prepared by the solid state diffusion (SSD) method is reported in this paper. The synthesized phosphors are studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. The emission spectra of Dy3+ show dominant peaks at 473nm and 572nm for an excitation of 274nm due to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively, while the emission spectra of Ce3+ peak at 345nm for an excitation of 254nm due to the 5d→4f transition of Ce3+. In this host very low concentration of cerium is used. In NaMg(SO4)F:Dy3+ a single peak is observed at the temperature of 170°C and in NaMg(SO4)F:Ce it is located at 172°C when they are exposed to γ-rays for 5Gy at the rate of 0.995kGyh−1. NaMg(SO4)F:Dy is more sensitive whereas, NaMg(SO4)F:Ce less sensitive as compared to standard CaSO4:Dy. NaMg(SO4)F:Dy phosphor may be useful for TLD application.