Horornis is a genus of small insectivorous songbirds ("warblers") which make up the core of the newly recognized family Cettiidae. They were formerly placed in the Sylviidae, which at that time was a wastebin taxon for the warbler-like Sylvioidea. The range of this genus occurs from southeast Asia throughout the western Pacific. The most recently described species is the Bougainville bush warbler (Horornis haddeni) from Bougainville Island.