Experimental thermodynamic data, related to the DyCl3-KCl system and the two pure components have been collected from the literature. Assessment of the collected data has been done using the thermodynamic ’surrounded-ion’ model (SIM) and the equations deduced from the thermodynamics of solutions. Gibbs free energy of formation of the two definite compounds K3DyCl6 and KDy3Cl10 and the excess entropy of the liquid have been optimized.