The Mg–Y binary system's potential has been developed within the framework of the second-nearest-neighbor modified embedded-atom method (MEAM) based on a potential for pure Mg. The potential fitting is done on a range of physical properties, either experimental or computed by first-principles methods. These include the Y interaction energy with basal and pyramidal stacking faults and properties of the B2 Mg–Y intermetallic phase. Using this model, one can make predictions generally in reasonable agreement with experiments and or DFT, but differences remain for subtle but important aspects of Y solutes in Mg.