Araucaria heterophylla (synonym A. excelsa) is a vascular plant in the ancient and now disjointly distributed conifer family Araucariaceae. As its vernacular name Norfolk Island pine (or Norfolk pine) implies, the tree is endemic to Norfolk Island, a small island in the Pacific Ocean between New Zealand and New Caledonia, about 1440 km east of Sydney, Australia. The genus Araucaria occurs across the South Pacific, especially concentrated in New Caledonia (about 700 km due north of Norfolk Island) where 13 closely related and similar-appearing species are found. It is sometimes called a star pine, Polynesian pine, triangle tree or living Christmas tree, due to its symmetrical shape as a sapling, although it is not a true pine.

It is a slow growing tree, reaching a height of 50–65 m, with straight vertical trunks and symmetrical branches, even in the face of incessant onshore winds that can contort most other species. From the straight trunk, it emits its branches almost horizontal or slightly oblique, in number of five, forming floors; the plane of each floor is a perfect pentagon. If kept indoors, the tree remains smaller. The gray-brown bark falls off in fine scales. At the more or less horizontal to sometimes hanging branches, the branches are four to seven in regular whorls.

The scientific name heterophylla ("different leaves") derives from the variation in the leaves between young and adult plants.