Trivalent dysprosium (Dy3+)-doped sodium-aluminum-phosphate (NAP) glasses were prepared and characterized by their optical absorption, excitation, emission spectra, and decay time measurements. Judd-Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative lifetime and stimulated emission cross section of the 4F9/2 → 6H13/2 and 4F9/2 → 6H15/2 transitions. The luminescence intensity ratio of 4F9/2 → 6H13/2 to 4F9/2 → 6H15/2 transitions of Dy3+ in NAP glasses gives the feasibility of extracting white light. The lifetime and quantum efficiency of 4F9/2 level is found to be higher than other reported glasses. With increase in Dy3+ ion concentration, the decay from 4F9/2 level is found to be faster with decrease in lifetime due to cross relaxation between Dy3+ ions. © 2011 Springer Science+Business Media, LLC.