A phylogenetic analysis was conducted of the Anthonomus grandis species group (Coleoptera: Curculionidae) and used to test various hypotheses concerning the evolution of these weevil species with their host plants. Phylogenetic analysis indicated that the five species of the A. grandis species group comprise two major clades. In the first clade, A. grandis Boheman is the sister taxon of A. hunteri Burke & Cate and A. mallyi Jones & Burke, and the second clade contains A. townsendi Jones & Burke and A. palmeri Jones & Burke. The proposed weevil phylogeny and knowledge of host associations strongly support the hypothesis that the genus Hampea (Malvales: Malvaceae), and not cotton ( Gossypium), is the original host plant genus of the A. grandis species group. Comparison of the phylogeny of the A. grandis group with that of a previously published phylogeny of Hampea showed little congruence, suggesting that the species of weevils are associated with Hampea as a result of host shifts and colonization processes, as opposed to co-speciation or coevolution (parallel cladogenesis). Mapping habitat associations and geographic distributions onto the phylogeny of the A. grandis group indicate that weevil preference for general habitat type (montane versus lowland habitats) and geographic proximity of species of Hampea were probably the principal factors responsible for observed associations of the weevils with their respective host plants. Possible characteristics of the A. grandis group, which may favor colonization as opposed to cospeciation processes in the association of its host plants, are discussed in light of these results.