Guinea, officially the Republic of Guinea, is a coastal country in West Africa. It borders the Atlantic Ocean to the west, Guinea-Bissau to the northwest, Senegal to the north, Mali to the northeast, Ivory Coast to the southeast, and Sierra Leone and Liberia to the south. It is sometimes referred to as Guinea-Conakry, after its capital Conakry, to distinguish it from other territories in the eponymous region, such as Guinea-Bissau and Equatorial Guinea. Guinea has a population of 14 million and an area of 245,857 square kilometres (94,926 sq mi).

Formerly French Guinea, it achieved independence in 1958. Guinea has a history of military coups d'état. After decades of authoritarian rule, it held its first democratic election in 2010. As it continued to hold multi-party elections, the country still faces ethnic conflicts, corruption, and abuses by the military and police. In 2011, the United States government claimed that torture by security forces and abuse of women and children (including female genital mutilation) were ongoing human rights issues. In 2021, a military faction overthrew president Alpha Condé and suspended the constitution.

Muslims represent 90% of the population. The country is divided into four geographic regions: Maritime Guinea on the Atlantic coast, the Fouta Djallon or Middle Guinea highlands, the Upper Guinea savanna region in the northeast, and the Guinée forestière region of tropical forests. French, the official language of Guinea, is the language of communication in schools, government administration, and the media. More than 24 indigenous languages are spoken, and the largest are Susu, Pular, and Maninka, which dominate respectively in Maritime Guinea, Fouta Djallon, and Upper Guinea, while Guinée forestière is ethnolinguistically diverse. Guinea's economy is mostly dependent on agriculture and mineral production. It is the world's second-largest producer of bauxite and has deposits of diamonds and gold. As of the most recent survey in 2018, 66.2% of the population is affected by multidimensional poverty, and an additional 16.4% are vulnerable to it.

Guinea is named after the Guinea region which lies along the Gulf of Guinea. It stretches north through the forested tropical regions and ends at the Sahel. The English term Guinea comes directly from the Portuguese word Guiné which emerged in the mid-15th century to refer to the lands inhabited by the Guineus, a generic term for the African peoples south of the Senegal River, in contrast to the "tawny" Zenaga Berbers above it, whom they called Azengues or Moors.^{[citation needed]}

In 1978, the official name became the People's Revolutionary Republic of Guinea. In 1984, the country was renamed the Republic of Guinea after the death of the first president, Ahmed Sékou Touré.

The land that is now Guinea either bordered or was situated within a series of historic African empires before the French arrived in the 1890s and claimed the terrain as part of colonial French West Africa. Guinea declared independence from France on 2 October 1958. From independence until the presidential election of 2010, Guinea was governed by multiple autocratic rulers.

What is now Guinea sat on the fringes of various West African empires. The earliest, the Ghana Empire, grew on trade and ultimately fell after repeated incursions of the Almoravids. It was in this period that Islam first arrived in the region by way of North African traders. The Sosso Empire came and stayed from 12th to 13th centuries; later, the Mali Empire came when Soundiata Kéïta defeated the Sosso ruler Soumangourou Kanté at the Battle of Kirina in c. 1235. The Mali Empire was ruled by Mansa (Emperors), including Kankou Moussa, who made a hajj to Mecca in 1324. After his reign, the Mali Empire began to decline and was ultimately supplanted by its vassal states in the 15th century.

The Songhai Empire expanded its power in about 1460. It continued to prosper until a civil war, over succession, followed the death of Askia Daoud in 1582. The empire fell to invaders from Morocco in 1591, but the kingdom later split into smaller kingdoms. After the fall of some of the West African empires, various kingdoms existed in what is now Guinea. Fulani Muslims migrated to Futa Jallon in Central Guinea, and established an Islamic state from 1727 to 1896 with a written constitution and alternate rulers. The Wassoulou or Wassulu Empire (1878–1898) was led by Samori Toure in the predominantly Malinké area of what is now upper Guinea and southwestern Mali (Wassoulou). It moved to Ivory Coast before being conquered by the French.