The fernwren (Oreoscopus gutturalis) is a species of bird in the family Acanthizidae. It is monotypic within the genus Oreoscopus.
It is endemic to northern Queensland in Australia. Its natural habitats are tropical moist lowland forest and tropical moist montane forest.
The fernwren has a white eyebrow and throat, enclosing a dark brown face. Beneath the white throat, it has a black bib. It has a long-slender bill. The upperparts are dark olive-brown and the underparts paler. It is 12–14 cm in length. The female is very similar to the male. Juveniles are dark brown without the white facial markings of the adult.