The Narrow-billed Antwren (Formicivora iheringi) is a species of bird in the Thamnophilidae family. It is endemic to eastern Brazil where it occurs in Bahia and Minas Gerais states. Its natural habitat is deciduous and semi-deciduous forest between 250 and 1,050 metres above sea level. It is threatened by habitat loss. The Narrow-billed Antwren is sometimes put in the monotypic genus Neorhopias.