The density, viscosity, and thermal conductivity of benzoic acid + water mixtures were measured at temperatures between 375 K and 465 K and concentrations ranging from 5 mass % benzoic acid to 100 mass % benzoic acid. Because the benzoic acid + water system exhibits a liquid-liquid immiscibility region at lower temperatures, care was exercised to ensure that the conditions chosen were in the single-phase region of the phase diagram. The data were correlated over the entire concentration range using the generalized corresponding states principle (GCSP).