DSC was used to study the phase equilibrium in the TbBr3-LiBr binary system. The results obtained provided a basis for constructing the phase diagram of this system. It exhibits two compounds: Li5TbBr8, which decomposes in the solid state at 611 K, and Li3TbBr6, which melts congruently at 785 K with the related enthalpy 59.1 kJ.mol(-1). The binary LiBr-TbBr3 system was then optimized using the available experimental information on phase diagram and thermodynamic properties. A two-sub-lattice ionic solution model (Li+)(P):(Br, TbBr63, TbBr3)(Q) was adopted to describe the liquid phase. The present assessment of the binary LiBr-TbBr3 system was in good agreement with the corresponding experimental data and confirmed their consistency. (C) 2012 Elsevier Ltd. All rights reserved.