Anas was named by Linnaeus (1758). It is extant. Its type is Anas platyrhynchos. It is the type genus of Anatidae, Anatinae, Anatoidea. It was considered unknown by Emslie (1998) and monophyletic by Eo et al. (2009).

It was assigned to Anseres by Shufeldt (1891); to Aves by Norell and Clarke (2001); to Anatinae by Hay (1930), Lambrecht (1933), Wetmore (1940), Wetmore (1956), Brodkorb (1964), Howard (1966), Brodkorb (1967), Peterson (1999) and Eo et al. (2009); to Ornithuromorpha by Wang et al. (2014); to Anatini by Hou (1985), Bickart (1990), Emslie (1992), Olson and Rasmussen (2001), Gonzalez et al. (2009), Zelenkov (2012), del Hoyo et al. (2014) and Worthy and Nguyen (2020); and to Anatidae by Hay (1902), De Vis (1905), Wetmore (1962), McCoy (1963), Parmalee (1992), Worthy (1997), Emslie (1998), Worthy and Grant-Mackie (2003), Göhlich (2009), Zelenkov and Kurochkin (2012), Zelenkov and Panteleyev (2015), Clements et al. (2017) and Tambussi et al. (2023).