Na-Dene (/ˌnɑːdɪˈneɪ/ NAH-dih-NAY; also Nadene, Na-Dené, Athabaskan–Eyak–Tlingit, Tlina–Dene) is a family of Native American languages that includes at least the Athabaskan languages, Eyak, and Tlingit languages. Haida was formerly included but is now generally considered a language isolate. By far the most widely spoken Na-Dene language today is Navajo, also the most spoken indigenous language north of Mexico.
Some linguists have proposed that the Na-Dene family is related to the Yeniseian languages of central Siberia, creating a Dene–Yeniseian family. However, this proposal has not been accepted by some linguists.