The Cayuga nation (Guyohkohnyo or the People of the Great Swamp) was one of the five original constituents of the Iroquois, a confederacy of Indians in New York. The Cayuga homeland lay in the Finger Lakes region between their league neighbors, the Onondaga and the Seneca.

Due to many attacks on American colonists during the American Revolution, the punitive Sullivan Expedition devastated the Cayuga homeland. Survivors fled to other Iroquois tribes or to Canada. Today, there are three Cayuga bands. The two largest are the Lower Cayuga and Upper Cayuga, both at Six Nations of the Grand River. Only a small number remain in New York with the Cayuga Nation in Versailles. After the Mohawks, the Cayugas are the most numerous people at Six Nations.

On November 11, 1794, the Cayuga Nation (along with the other Haudenosaunee nations) signed the Treaty of Canandaigua with the United States.

One current spelling of the Cayuga name for "Cayuga" is Gayogohó:no'.