The invasion of exotic plants threatens biodiversity, affecting ecosystem services and ecological processes in native ecosystems. Road construction creates new environments and contributes to the introduction and spread of exotic and invasive plants. This study aimed to analyze the contribution of different functional groups (annual herbs and grasses, perennial herbs and grasses, shrubs, trees) to the invasion of exotic species on roadside cut slopes in the Austrocedrus chilensis forest in northwest Andean Patagonia, Argentina. Roadside slopes (RSs) and nearby reference areas (RAs) were selected, and the cover of native, exotic, and invasive species from the functional groups was evaluated in 1 m² plots using the Braun-Blanquet method. It was found that invasive perennial herbs and grasses predominated on RS, with a cover (19.6±3.0%) higher than that of RA (8.9±1.5%). Agrostis capillaris and Rumex acetosella were the most abundant invasive species. Among native species, shrubs and perennial herbs and grasses were predominant on RS, with Baccharis rhomboidalis and Acaena pinnatifida being the most abundant. This study demonstrates that the roadside slopes of the Austrocedrus chilensis forest harbor invasive exotic species that can invade nearby natural areas. Early detection of these species is important for proper management and control, thus promoting the conservation of biodiversity in forest environments.