Around 40 variants of the name Kutenai have been attested since 1820; two others are also in current use. Kootenay is the common spelling in British Columbia, including in the name of the Lower Kootenay First Nation. Kootenai is used in Montana and Idaho, including in the Kootenai Tribe of Idaho and the Confederated Salish and Kootenai Tribes. These two spellings have been used for various placenames on their respective sides of the Canadian-U.S. border. Kutenai is the common form in the literature about the people, and has been adopted by Kutenai in both countries as an international spelling when discussing the people as a whole. The name evidently derives from the word for the people, Kotonáwa, which itself may derive from the Kutenai term Ktunaxa.
There are two words in the Kutenai language for the people and their language: Ktunaxa and Ksanka. Ktunaxa is the primary form for the British Columbia groups. Two etymologies have been suggested, tying the name to a verb for "to go out into the open", or to a verb for "to eat lean meat". Ksanka is the word used by the Montana people.