Vapor pressure data were measured for binary and ternary systems containing water, methanol, ethanol, and a halogen-free ionic liquid (IL) triethylmethylammonium dimethylphosphate ([N(1222)][DMP]) with IL content ranging from mass fractions of (0.1 to 0.5) at varying temperatures, using a quasi-static ebulliometer. The vapor pressure data of IL-containing binary systems were well-correlated by the nonrandom two-liquid (NRTL) equation with an overall average absolute relative deviation (AARD) of 0.0088, and the resulting binary parameters were used to predict the vapor pressure of three ternary systems with an overall AARD less than 0.0169. Further, the isobaric vapor-liquid equilibrium (VLE) data for ternary systems {water + ethanol + [Nun] [DMP]} and {methanol + ethanol + [N(1222)] [DMP]} with IL mass fractions of 0.1, 0.3, and 0.5 at 101.3 kPa were predicted, respectively. It is demonstrated that the relative volatilities of ethanol to water and ethanol to methanol are enhanced. Therefore, a separation of the azeotrope of {water + ethanol} mixture can be sufficiently facilitated by the addition of [N(1222)] [DMP] at a specified content.