Surface tensions of solutions of oxalic, malonic, succinic, glutaric and adipic acids in water and water + acetone (x(acetone) = 0.016, 0.033, 0.072, 0.117 and 0.171) mixtures at different temperatures for varying ranges of concentrations have been measured by means of the ring detachment method. The data were analyzed using Gibbs equations and various thermodynamic functions have been evaluated. The results reveal the nature of solute adsorption at the interface in these solvents.