of galvanic cells with the solid electrolyte (ZrO2+CaO) was measured to determine the activities of gallium at high temperatures in the whole composition range for liquid Ga-Te and Ga-Sb alloys, and some thermodynamic functions were derived from the results. The cells used were as follows:The activities of gallium in liquid Ga-Te alloys at 1123 K showed large negative deviations from Raoult's law on the Te-rich side, and increased remarkably in the middle concentration range from negative to positive deviations from ideality. The activities of gallium in liquid Ga-Sb alloys at 1073 K showed moderate negative deviations from the ideality in the whole composition range. These data are compared with published data.