A database of atomic mobility parameters for single phase Mg–X (X=Ag, Al, Be, Cd, Ce, In, Fe, Ga, La, Mn, Ni, Sb, Sn, U, and Zn) systems was developed through the critical assessment of available Mg diffusion literature. Optimization of the binary diffusion activation energy terms for Ag, Al, Sn, and Zn solutes, as well as the Al–Zn interaction parameter were completed through the coupling of an existing thermodynamic database with the DICTRA software program. In general, agreement between simulated and experimental diffusion profiles was observed, although limitations for extrapolation to higher order systems were seen due to the limited multicomponent diffusion studies in Mg. This work, however, ultimately provides the foundation for the integration of diffusion simulations and predictions in future Mg alloy design. Further research to expand the current database, through either the experimental measurement or simulation of multicomponent diffusion and diffusivity in other phases (e.g. intermetallics, liquid), is expected to increase the database utility.