The N-functionalization of free sulfoximines is an important approach to modifying their chemical and biological properties for downstream applications. Here, we report a rhodium-catalyzed N-allylation of free sulfoximines (═NH) with allenes under mild conditions. The redox-neutral and base-free process enables chemo- and enantioselective γ-hydroamination of allenes and gem-difluoroallenes. Synthetic applications of sulfoximine products obtained thereof have been demonstrated.