In order to understand the chemical interactions between Fe and Sm and Fe and Dy, the Fe-Sm and Fe-Dy systems were critically evaluated and optimized based on all available and reliable literature experimental data. The Modified Quasichemical Model was employed to model the liquid phase. From the thermodynamic modelling, a consistent thermodynamic description of the intermetallic and liquid phases occurring in the respective binary systems was obtained, which can be integrated in multicomponent Rare Earth (RE) metal systems.