Precise vapor pressure data for LiBr solutions in ethanol are given for temperatures ranging from 298.15 to 348.15 K. The molality range investigated is from 0.0705 to 3.4451 mol-kg−1. Osmotic coefficients are calculated by taking into account the second virial coefficient of ethanol. The parameters of the extended Pitzer ion-interaction model of Archer, the MSA-NRTL model, and the chemical model of Barthel are evaluated and discussed. The parameters of the extended Pitzer ion-interaction model of Archer are used to calculate the mean molal activity coefficients. Osmotic and activity coefficients both decrease with increasing temperature in this temperature range.