Lambertia formosa, commonly known as mountain devil, is a shrub of the family Proteaceae, endemic to New South Wales, Australia. First described in 1798 by English botanist James Edward Smith, it is the type species of the small genus Lambertia. It is generally found in heathland or open forest, growing in sandstone-based soils. It grows as a multistemmed shrub to around 2 m (7 ft) with a woody base known as a lignotuber, from which it regrows after bushfire. It has stiff narrow leaves, and the pink to red flowerheads, made up of seven individual tubular flowers, generally appear in spring and summer. It gains its common name from the horned woody follicles, which were used to make small devil-figures.