Eyak is a Na-Dené language that was historically spoken in southern Alaska, near the mouth of the Copper River.

Today, the language has only one surviving elderly speaker, Marie Smith. Because of the dying off of its native speakers, Eyak has become a poster child for the fight against language extinction.

The closest relatives of Eyak are the Athabaskan languages. The Eyak-Athabaskan cluster, together with Tlingit, forms a basic division of the Na-Dene language phylum.