Whooper Swan (Cygnus cygnus) is a large Northern Hemisphere swan. It is the Old World counterpart of the North American Trumpeter Swan.

Whooper is similar in appearance to the Bewick's Swan. However, it is larger, at 140-160cm length and a 205-235cm wingspan. It has a more angular head shape and a more variable bill pattern that always shows more yellow than black (Bewick's Swans have more black than yellow).

Their breeding habitat is wetland. They pair for life, and their cygnets stay with them all winter; they are sometimes joined by offspring from previous years.

Whooper Swans breed in subarctic Eurasia, further south than Bewick's in the taiga zone. They are migratory wintering in northern Europe and eastern Asia. This bird is an occasional vagrant to western North America.

Icelandic breeders overwinter in England and Ireland, especially in the wildfowl reserves of the Royal Society for the Protection of Birds and of the Wildfowl and Wetlands Trust.

These birds feed mainly by grazing on farmland on coasts or inland flood plains. They have a deep honking call.

The Whooper Swan is the national bird of Finland.