Crow (native name: Apsáalooke [ə̀ˈpsâːɾòːɡè] or [ə̀ˈpsâːlòːɡè]) is a Missouri Valley Siouan language spoken primarily by the Crow Tribe in present-day southeastern Montana. The word Apsáalooke translates to "Children of the Large Beaked Bird" (from apá 'beak/nose', isáa 'big', dooká 'child'), which was later incorrectly translated into English as 'Crow'. It is one of the larger populations of American Indian languages with around 3,650 speakers according to the 2017-2021 American Community Survey.

Crow is closely related to Hidatsa spoken by the Hidatsa tribe of the Dakotas; the two languages are the only members of the Missouri Valley Siouan family. Despite their similarities, Crow and Hidatsa are not mutually intelligible.

The Crow people historically constituted two main groups: the River Crow and the Mountain Crow. However, most authors report that dialectal differences between the two groups are few.

According to Ethnologue with figures from 1998, 77% of Crow people over 66 years old speak the language; "some" parents and older adults, "few" high school students and "no pre-schoolers" speak Crow. 80% of the Crow Tribe prefers to speak in English. The language was classified as "definitely endangered" by UNESCO as of 2012.

However, R. Graczyk claims in his A Grammar of Crow (2007) that "unlike many other native languages of North America in general, and the northern plain in particular, the Crow language still exhibits considerable vitality: there are fluent speakers of all ages, and at least some children are still acquiring Crow as their first language." Many of the younger population who do not speak Crow are able to understand it. Almost all of those who do speak Crow are also bilingual in English. Graczyk cites the reservation community as the reason for both the high level of bilingual Crow-English speakers and the continued use and prevalence of the Crow language. Daily contact with non–American Indians on the reservation for over one hundred years has led to high usage of English. Traditional culture within the community, however, has preserved the language via religious ceremonies and the traditional clan system.

Currently, most speakers of Crow are 30 and older but a few younger speakers are learning it. There are increased efforts for children to learn Crow as their first language and many do on the Crow Reservation of Montana, particularly through a Crow language immersion school that was sponsored in 2012. Development for the language includes a Crow language dictionary and portions of the Bible published from 1980–2007. The current literacy rate is around 1–5% for first language speakers and 75–100% for second language learners. Teens are immersed in Crow at the Apsaalooke language camp sponsored by the Crow Tribe.

Crow is closely related to Hidatsa spoken by the Hidatsa tribe of the Dakotas; the two languages are the only members of the Missouri Valley Siouan family. The ancestor of Crow-Hidatsa may have constituted the initial split from Proto-Siouan. Crow and Hidatsa are not mutually intelligible, however the two languages share many phonological features, cognates and have similar morphologies and syntax. The split between Crow and Hidatsa may have occurred between 300 and 800 years ago.

There are eight distinct vowels in Crow, three short and five long, along with two diphthongs. The mid vowels [eː] and [oː] do not have phonemic short counterparts, but they may be phonetically shortened preceding a coda consonant.