The solubilities of 5,10,15,20-tetraphenylporphyrin (TPP) and 5,10,15,20-tetraphenylporphyrin manganese(III) chloride (TPPMnCl) in binary ethanol + water solvent mixtures at (303.2 to 333.2) K were determined at atmospheric pressure. The solubility of TPPMnCl in ethanol + water solvent mixtures is much larger than that of TPP. The effects of temperature and mass fraction of ethanol in the solvent mixtures on the solubilities were studied. It was found that the solvent composition has a significant influence on solubility. The solubility of TPP increases apparently with the increasing temperature for a certain solvent composition; however, the solubility of TPPMnCl only slightly increases with the increase of temperature at constant composition. The experimental data were correlated with the Nyvlt equation, and good agreement between the experimentally determined and the correlated solubilities was obtained. Furthermore, the thermodynamic parameters including dissolution enthalpy, dissolution entropy, isobaric heat capacity, and Gibbs free energy of TPP and TPPMnCl in ethanol + water mixtures were calculated by the Clark-Glew equation.