Excess molar enthalpies H-E as a function of composition for the two ternary systems, phenol-1-hexanol-n-heptane and phenol-cyclohexanol-n-heptane, and five constituent binaries have been measured with a Calvet-type microcalorimeter at 318.15 K. All the excess enthalpies of binary systems containing n-heptane are positive, including those for a partially miscible system, phenol-n-heptane. The H-E values of phenol-alcohol systems are negative. The results have been used to predict ternary H-E data by the UNIFAC model and a version of this, the UNIFAC(3Q), both with enthalpy-fitted interaction parameters. It was found that the models could only qualitatively predict the ternary H-E values.