This work presents new data on the solid-phase equilibria of the Tl-Tb-Te ternary system in the Tl2Te-Tl2Te3-TlTbTe2 composition region and the thermodynamic functions of the TlTbTe2, and Tl9TbTe6 ternary compounds. Studies were carried out by using the electromotive forces method (EFM) and the powder x-ray diffraction technique. From the EMF measurements of the concentration cells of the type (−) TbTe (s) | glycerol + KCl + TbCl3 | (Tb in Tl-Tb-Te alloys) (s) (+) in the 300-450 K temperature interval, the relative partial thermodynamic functions of TbTe and Tb in alloys of the Tl2Te3-TlTe-TlTbTe2, and TlTe-TlTbTe2-Tl9TbTe6 three-phase regions were determined. Based on the solid-phase equilibria diagram, the potential-forming reactions responsible for the indicated partial molar quantities were determined and the standard thermodynamic functions of formation and standard entropies of the TlTbTe2 and Tl9TbTe6 ternary compounds were calculated.