The Fe–Nd–Sb system was assessed by means of the CALculation of PHAse Diagram (CALPHAD) technique. The solution phase, liquid, bcc, fcc, dhcp, and rhom, were described by the substitutional solution model. The compounds Fe17Nd2, Fe17Nd5, Nd2Sb, Nd5Sb3, Nd4Sb3, NdSb, NdSb2, Nd6Fe13Sb (τ1), Nd3Fe3Sb7 (τ3), NdFeSb3 (τ4), and NdFe4Sb12 (τ6) were treated as stoichiometric compounds. The ternary compounds Nd2Fe5−xSb10−y (τ2, x = 1.48, y = 5.12) and NdFe1−xSb2 (τ5) were modeled as (Fe,Va)0.4667(Nd)0.1333(Sb,Va)0.4 and (Fe,Va)0.25(Nd)0.25(Sb)0.5, respectively. A set of self-consistent thermodynamic parameters of the Fe–Nd–Sb system was obtained in this study.