The American (North and South America) horned owls and the Old World eagle-owls make up the genus Bubo, at least as traditionally described. The genus name Bubo is Latin for owl.

This genus contains 10 species that are found in many parts of the world. Some of the largest living Strigiformes are in Bubo. Traditionally, only owls with ear-tufts were included in this genus, but that is no longer the case.

The genus Bubo was introduced in 1805 by the French zoologist André Duméril for the horned owls. The type species is the Eurasian eagle-owl. The word bubo is Latin for the Eurasian eagle owl and was used as the specific epithet for the species by Carl Linnaeus in 1758.

A molecular phylogenetic study published in 2020 found that species in the genera Scotopelia and Ketupa were embedded within the clade containing members of the genus Bubo making the genus Bubo paraphyletic. To create monophyletic genera, nine species were moved from Bubo to Ketupa.

The genus contains 10 extant species:

Sometimes included in this genus:

Named and distinct Bubo species are:

Some notable undescribed fossils of prehistoric horned owls, usually quite fragmentary remains, have also been recorded: