With the use of the drop calorimetry method, measurements of the mixing enthalpy change were carried out for the liquid Ga-In-Li liquid solutions. The experiments were conducted for five different cross sections and at temperatures higher than 1000 K. The alloys investigated were as follows: (Ga0.75Li0.25)(1-x)In-x at 1005 K, (In0.75Li0.25)(1-x)Ga-x at 1005 K, (Ga0.50Li0.50)(1-x)In-x at 1005 K, (Ga0.25Li0.75)(1-x)In-x at 1026 K and (In0.30Li0.70)(1-x)Ga-x at 1031 K. The mixing enthalpy change, measured for all the cross sections of the Ga-In-Li system, is characterized by a negative deviation from the ideal solutions. Based on the optimized thermo dynamic parameters of binary liquid solutions in the form of the Redlich-Kister equation and the experimental data determined in these studies, the ternary interaction parameters of the Toop model were elaborated. An agreement between the calculated and experimental data can be established as well, taking into account the degree of measurement difficulty. (c) 2021 Elsevier B.V. All rights reserved.