In the present work, the ternary system Fe-Al-Nb was modeled with the Calphad approach based on new experimental data including the invariant reaction scheme, liquidus surface, and isothermal sections. In order to get a reasonable description for the ternary system, the Fe-Nb binary system had to be updated to improve the description of the C14 Laves phase. Recent experimental results on the solvus of the C14 phase as well as new ab initio data were taken into account together with all other available experimental information. A complete thermodynamic description of the Fe-Al-Nb system is obtained, and extensive comparisons between calculated and experimental data are presented showing that almost all the available experimental and theoretical data are satisfactorily fitted.