It also includes bark beetles, which while morphologically dissimilar to other weevils in lacking the distinctive snout, is a subfamily of Curculionidae.

One species of weevil, Austroplatypus incompertus, exhibits eusociality, one of the few insects outside the Hymenoptera and the Isoptera to do so.

Because so many species exist in such diversity, the higher classification of weevils is in a state of flux.

A 1995 classification system to family level was provided by Kuschel,[5] with updates from Marvaldi et al. in 2002,[6] and was achieved using phylogenetic analyses.

[8] The oldest weevils date to the Middle-Late Jurassic boundary, found in the Karabastau Formation of Kazakhstan, the Shar-Teg locality of Mongolia, the Daohugou locality in Inner Mongolia, China, and the Talbragar site in Australia.

[9] The extinct family Obrieniidae, with species dating from the Ladinian stage of the Triassic through to tentatively the Oxfordian, have sometimes been considered weevils.

[6][7][12][13][14] The phylogeny by Li et al. (2023) based on phylogenomic data is suggested below:[14] Cimberididae Nemonychidae Anthribidae Belidae Attelabidae Caridae Brentidae Curculionidae Rhopalapion longirostre exhibits an extreme case of sexual dimorphism.