Eucalyptus snout beetles (Curculionidae: Gonipterus scutellatus complex), native to mainland Australia and Tasmania, defoliate Eucalyptus trees and are considered important pests. Since the 19th century, species of the G. scutellatus complex have been introduced to other continents. Here, we document the presence of Eucalyptus snout beetles in Ecuador and use ecological niche models to analyze their potential distribution in South America. Phylogenetic analyses of DNA sequences unambiguously demonstrated that the Ecuadorian specimens belong to the species G. platensis, which has low genetic diversity compared with other species in the complex. Ecological niche models revealed several areas of high to intermediate climatic suitability for the pest in South America, even in countries where it has not been registered, like Peru and Bolivia. Accurate identification of species in the Gonipterus scutellatus complex and understanding of their potential distribution are essential tools for improved management and prevention tactics.