The yellow-billed pintail was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[2] Gmelin based his description on the "Georgia duck" that had been described in 1785 by the English ornithologist John Latham in his A General Synopsis of Birds.

[3][4] The naturalist Joseph Banks had provided Latham with a water-colour drawing of the duck by Georg Forster who had accompanied James Cook on his second voyage to the Pacific Ocean.

The species is sometimes confused with yellow-billed teal (Anas flavirostris) but can be differentiated by the yellow stripes on its bill, its larger size, and its tendency not to form large groups.

The Chilean, or brown, pintail A. g. spinicauda is widespread on the South American mainland from extreme southern Colombia southwards, as well as in the Falkland Islands, and numbers well over 110,000.