Armenians (Armenian: հայեր, romanized: hayer, [hɑˈjɛɾ]) are an ethnic group indigenous to the Armenian highlands of West Asia. Armenians constitute the main demographic group in Armenia and constituted the main population of the breakaway Republic of Artsakh until their subsequent flight due to the 2023 Azerbaijani offensive. There is a large diaspora of around five million people of Armenian ancestry living outside the Republic of Armenia. The largest Armenian populations exist in Russia, the United States, France, Georgia, Iran, Germany, Ukraine, Lebanon, Brazil, Argentina, Syria, and Turkey. The present-day Armenian diaspora was formed mainly as a result of the Armenian genocide with the exceptions of Iran, former Soviet states, and parts of the Levant.

Armenian is an Indo-European language. It has two mutually intelligible spoken and written forms: Eastern Armenian, today spoken mainly in Armenia, Artsakh, Iran, and the former Soviet republics; and Western Armenian, used in the historical Western Armenia and, after the Armenian genocide, primarily in the Armenian diasporan communities. The unique Armenian alphabet was invented in 405 AD by Mesrop Mashtots.

Most Armenians adhere to the Armenian Apostolic Church, a non-Chalcedonian Christian church, which is also the world's oldest national church. Christianity began to spread in Armenia soon after Jesus' death, due to the efforts of two of his apostles, St. Thaddeus and St. Bartholomew. In the early 4th century, the Kingdom of Armenia became the first state to adopt Christianity as a state religion, followed by the first pilgrimages to the Holy Land where a community established the Armenian Quarter of Old Jerusalem.

The earliest attestations of the exonym Armenia date around the 6th century BC. In his trilingual Behistun Inscription dated to 517 BC, Darius I the Great of Persia refers to Urashtu (in Babylonian) as Armina (Old Persian: 𐎠𐎼𐎷𐎡𐎴) and Harminuya (in Elamite). In Greek, Armenios (Αρμένιοι) is attested from about the same time, perhaps the earliest reference being a fragment attributed to Hecataeus of Miletus (476 BC). Xenophon, a Greek general serving in some of the Persian expeditions, describes many aspects of Armenian village life and hospitality in around 401 BC.

Some have linked the name Armenia with the Early Bronze Age state of Armani (Armanum, Armi) or the Late Bronze Age state of Arme (Shupria). Armini, Urartian for "inhabitant of Arme" or "Armean country", referring to the region of Shupria, to the immediate west of Lake Van. The Arme tribe of Urartian texts may have been the Urumu, who in the 12th century BC attempted to invade Assyria from the north with their allies the Mushki and the Kaskians. The Urumu apparently settled in the vicinity of Sason, lending their name to the regions of Arme and the nearby lands of Urme and Inner Urumu. The location of the older site of Armani is a matter of debate. Some modern researchers have placed it in the same general area as Arme, near modern Samsat, and have suggested it was populated, at least partially, by an early Indo-European-speaking people. The relationship between Armani and the later Arme-Shupria, if any, is undetermined. Additionally, their connections to Armenians is inconclusive as it is not known what languages were spoken in these regions.

It has also been speculated that the land of Ermenen (located in or near Minni), mentioned by the Egyptian pharaoh Thutmose III in 1446 BCE, could be a reference to Armenia.

Armenians call themselves Hay (Armenian: հայ, pronounced [ˈhaj]; plural: հայեր, [haˈjɛɾ]). The name has traditionally been derived from Hayk (Armenian: Հայկ), the legendary patriarch of the Armenians and a great-great-grandson of Noah, who, according to Movses Khorenatsi (Moses of Khorene), defeated the Babylonian king Bel in 2492 BC and established his nation in the Ararat region. It is also further postulated that the name Hay comes from, or is related to, one of the two confederated, Hittite vassal states—Hayasa-Azzi (1600–1200 BC). Ultimately, Hay may derive from the Proto Indo-European words póti (meaning "lord" or "master") or *h₂éyos/*áyos (meaning "metal").

Khorenatsi wrote that the word Armenian originated from the name Armenak or Aram (the descendant of Hayk). Khorenatsi refers to both Armenia and Armenians as Hayk‘ (Armenian: Հայք) (not to be confused with the aforementioned patriarch, Hayk).^{[citation needed]}