Aleuts (/ˌæ.liːˈuːt/ ^ⓘ AL-ee-OOT; Aleut: Unangan (west) or Unangas (east) Russian: Алеуты, romanized: Aleuty) are the Indigenous people of the Aleutian Islands, which are located between the North Pacific Ocean and the Bering Sea. Both the Aleuts and the islands are politically divided between the US state of Alaska and the Russian administrative division of Kamchatka Krai. This group is also known as the Unangax̂ in Unangam Tunuu, the Aleut language. There are 13 federally recognized Aleut tribes in the Aleut Region of Alaska. In 2000, Aleuts in Russia were recognized by government decree as a small-numbered Indigenous people.

In the Aleut language, they are known by the endonyms Unangan (eastern dialect) and Unangas (western dialect); both terms mean "people". The Russian term "Aleut" was a general term used for both the native population of the Aleutian Islands and their neighbors to the east in the Kodiak Archipelago, who were also referred to as "Pacific Eskimos" or Sugpiat/Alutiit.

Aleut people speak Unangam Tunuu, the Aleut language, as well as English and Russian in the United States and Russia respectively. An estimated 150 people in the United States and five people in Russia speak Aleut. The language belongs to the Eskaleut language family and includes three dialects: Eastern Aleut, spoken on the Eastern Aleutian, Shumagin, Fox and Pribilof Islands; Atkan, spoken on Atka and Bering islands; and the now extinct Attuan dialect.

The Pribilof Islands has the highest number of active speakers of Unangam Tunuu. Most native elders speak Aleut, but it is rare for common people to speak the language fluently.

Beginning in 1829, Aleut was written in the Cyrillic script. From 1870, the language has been written in the Latin script. An Aleut dictionary and grammar have been published, and portions of the Bible were translated into Aleut.

Aleut (Unangan) dialects and tribes:

Aleuts historically lived throughout the Aleutian Islands, the Shumagin Islands, and the far western part of the Alaska Peninsula, with an estimated population of around 25,000 prior to European contact. In the 1820s, the Russian-American Company administered a large portion of the North Pacific during a Russian-led expansion of the fur trade. They resettled many Aleut families to the Commander Islands (within the Aleutsky District of the Kamchatka Krai in Russia) and to the Pribilof Islands (in Alaska). These continue to have majority-Aleut communities.

According to the 2000 census, 11,941 people identified as being Aleut, while 17,000 identified as having partial Aleut ancestry. Prior to sustained European contact, approximately 25,000 Aleut lived in the archipelago. The Encyclopædia Britannica Online states that more than 15,000 people have Aleut ancestry in the early 21st century. Aleuts suffered high fatalities in the 19th and early 20th centuries from Eurasian infectious diseases to which they had no immunity. In addition, the population suffered as their customary lifestyles were disrupted. Russian traders, and later Europeans, married Aleut women and had families with them.