Organisms deploy chemical defenses against pathogens and competitors, often resulting in coevolutionary arms races. When introduced into new environments, non-native species may possess ‘novel weapons’ against which native species have not evolved resistance. Ants use antifungal secretions and microbial symbionts to defend against pathogens, but their broader effects on soil fungi are less understood. We tested whether the invasive ant Myrmica rubra suppressed native fungi more strongly than the native ant Aphaenogaster picea using laboratory assays in which colonies of each species were exposed to agar plates inoculated with a native saprotroph, Absidia sp. Across high- and low-resource replicates, A. picea had no effect on Absidia growth relative to controls, whereas M. rubra reduced fungal cover, supporting the prediction that non-native ants exert stronger antifungal effects. Moreover, M. rubra facilitated non-target fungi colonization, including Aspergillus, Clonostachys, and Simplicillium species. Finally, phylogenetic analysis confirmed that M. rubra restructured fungal communities into distinct fungal assemblages. These results suggest that invasive ants may suppress native fungi while facilitating tolerant or self-benefiting, potentially reinforcing their ecological success. These findings underscore the role of microbial interactions in ant invasions and soil community dynamics.