Plant range-expansion is occurring at a rapid pace, largely in response to human-induced climate warming. While the movement of plants is well documented, their interactions with belowground microorganisms, which may influence the success of plant species in their new habitats, remains largely unknown. Here we used a latitudinal gradient to examine bacterial and fungal communities in the rhizosphere and soils of range-expanding plant species. We selected range-expanders with and without congeneric natives in the new range, and as a control, the congeneric natives, totaling 382 plant individuals collected across Europe. When taken together, our results suggest that the relatedness of range-expanding plants with the native community should be considered when assessing the effects of range-expansion on ecosystems.