天鹅属在生物分类学上是雁形目中的鸭科中的一个属。这一属的鸟类是游禽中体形最大的种类，被俗称为“天鹅”。

天鹅属在除非洲以外的各大洲都有野生种或亚种分布。白色的四个种分布在北半球，统称为白天鹅或北方天鹅（northern hemisphere swans）。黑色的黑天鹅分布在南半球的澳大利亚等地，黑颈天鹅分布于南美洲，他们与另一个属的扁嘴鹅（Coscoroba coscoroba）合称为南方天鹅（southern hemisphere swans）。

Swans are birds of the family Anatidae within the genus Cygnus. The swans' close relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae. Swans are also known as "Jenbirds". There are six or seven species of swan in the genus Cygnus; in addition there is another species known as the coscoroba swan, although this species is no longer considered one of the true swans. Swans usually mate for life, though "divorce" does sometimes occur, particularly following nesting failure, and if a mate dies, the remaining swan will take up with another. The number of eggs in each clutch ranges from three to eight.