The northern cassowary, also known as the one-wattled cassowary, single-wattled cassowary, or golden-necked cassowary, is a large, stocky flightless bird of northern New Guinea. It is one of the three living species of cassowary, alongside the dwarf cassowary and the southern cassowary. It is a member of the superorder Paleognathae.

Cassowaries are flightless birds of the genus Casuarius in the order Casuariiformes. They are classified as ratites: flightless birds without a keel on their sternum bones. Cassowaries are native to the tropical forests of New Guinea, the Aru Islands (Maluku), and northeastern Australia.