Cahto (also spelled Kato) is an extinct Athabaskan language that was formerly spoken by the Kato people of the Laytonville and Branscomb area at the head of the South Fork of the Eel River. It is one of the four languages belonging to the California Athabaskan cluster of the Pacific Coast Athabaskan languages. Most Kato speakers were bilingual in Northern Pomo and some also spoke Yuki. It went extinct in the 1960s.

Cahto has 26 consonant phonemes and 30 phones.

Cahto has 9 vowel phonemes (including the diphthong) and 12 phones.