Solubility of phenylphosphonic acid (PPOA) in 15 solvents (methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, acetone, and 1,4-dioxane) was measured by the isothermal saturation method under 0.1 MPa. Solubility of PPOA increased with increasing temperature. The interaction energies between PPOA and selected solvents were calculated by molecular simulation to explain the solubility order. Experimental solubility was correlated by five thermodynamic models including the modified Apelblat equation, uniquac, the nonrandom two-liquid (NRTL)-segment activity coefficient (SAC), NRTL, and the Wilson model. The modified Apelblat equation, NRTL, and NRTL-SAC were more applicable for fitting of solubility data of PPOA. Thermodynamic properties of the mixing process including the mixing Gibbs energy (Delta(mix)G), mixing enthalpy (Delta H-mix), and mixing entropy (Delta S-mix) were investigated by the Wilson equation. The mixing process was spontaneous, exothermic, and entropy-driven.