Ecosystem ecologists and restoration practitioners have become increasingly interested in the effects that invading species might have on soil processes. Invading species, particularly ones that differ from native species in traits that are likely to influence soil processes, may influence nitrogen cycling to such an extent that the legacy of the invasion persists long after invaders have been removed. We suggest that exotic species that are capable of altering soil nitrogen (N) pools, whether by augmenting ecosystem N through fixation of atmospheric N or by increasing rates of N losses, have the greatest capacity to interfere with restoration efforts. In contrast, cases where more subtle differences in tissue quality or quantity alter soil N fluxes but not total N pools may not exhibit a legacy long after removal of the exotic species. Given the challenges that invading species' effects on soils present to restoration efforts, it is important to develop predictions as to which invaders are likely to influence N dynamics after their removal and to develop techniques to minimize the influence of exotics on restored ecosystems.