Abstract: The thermodynamic properties and the phase diagrams of the systems Ga-M (M = In, Sb, Ph) were critically re-assessed and optimized employing the software package ChemSage for the calculation of thermodynamic equilibria. The Redlich-Kister/Margules formalism was employed for all solution phases and sets of self-consistent thermodynamic parameters were obtained. The results of re-assessment and optimization are compared with previous work, they are in excellent agreement with most experimental data.