Gaultheria is a genus of about 135 species of shrubs in the family Ericaceae. The name commemorates Jean-François Gauthier of Quebec, an honour bestowed by the Scandinavian Pehr Kalm in 1748 and taken up by Carl Linnaeus in his Species Plantarum. These plants are native to Asia, Australasia and North and South America. In the past, the Southern Hemisphere species were often treated as the separate genus Pernettya, but there is no consistent reliable morphological or genetic difference to support recognition of two genera, and they are now united in the single genus Gaultheria.
The species vary from low, ground-hugging shrubs less than 10 centimetres (3.9 in) tall, up to 2.5 metres (8 ft 2 in) tall, or, in the case of G. fragrantissima from the Himalaya, even a small tree up to 5–6 m (16–20 ft) tall. The leaves are evergreen, alternate (opposite in G. oppositifolia from New Zealand), simple, and vary between species from 3 millimetres (0.12 in) to 10 cm (3.9 in) long; the margins are finely serrated or bristly in most species, but entire in some. The flowers are solitary or in racemes, bell-shaped, with a five-lobed (rarely four-lobed) corolla; flower colour ranges from white to pink to red. The fruit is a fleshy berry in many species, a dry capsule in some, with numerous small seeds.