Geese are waterfowl belonging to the tribe Anserini of the family Anatidae. This tribe comprises the genera Anser (the grey geese), Branta (the black geese) and Chen (the white geese). A number of other birds, mostly related to the shelducks, have "goose" as part of their name. More distantly related members of the Anatidae family are swans, most of which are larger than true geese, and ducks, which are smaller.

There are three living genera of true geese: Anser, grey geese, including the domesticated goose and the Swan Goose; Chen, white geese (often included in Anser); and Branta, black geese, such as the Canada goose.

Two genera of "geese" are only tentatively placed in the Anserinae; they may belong to the shelducks or form a subfamily on their own: Cereopsis, the Cape Barren Goose, and Cnemiornis, the prehistoric New Zealand Goose.

Either these or, more probably, the goose-like Coscoroba Swan is the closest living relative of the true geese.