Cacomantis is a genus of cuckoos in the family Cuculidae. The name is from the Ancient Greek κακομαντις (kakomantis) meaning "prophet of evil". Most species have a round nostril and are mainly in brown and gray colours. The tails are graduated and barred. The bars are transverse in sonneratii and oblique in all others.

The genus Cacomantis was introduced in 1843 by the German naturalist Salomon Müller. He did not specify a type species; this was subsequently designated as Cuculus flavus Gmelin, a junior synonym of Cuculus merulinus Scopoli (the plaintive cuckoo). The genus name is from the Ancient Greek kakomantis meaning "prophet of doom". Müller explained that local people on the Maluku Islands thought of these species as "birds of misfortune" due to their mournful calls and their frequent presence in cemeteries.

The genus contains 11 species:

The pallid cuckoo (Heteroscenes pallidus) and the white-crowned cuckoo (Caliechthrus leucolophus) were formerly placed in this genus. They are now each placed in their own monotypic genus.