Antananarivo (Malagasy: [antananaˈrivʷ]; French: Tananarive, pronounced [tananaʁiv]), also known by its colonial shorthand form Tana (pronounced [tana]), is the capital and largest city of Madagascar. The administrative area of the city, known as Antananarivo-Renivohitra ("Antananarivo-Mother Hill" or "Antananarivo-Capital"), is the capital of Analamanga region. The city sits at 1,280 m (4,199 ft) above sea level in the center of the island, making it the highest national capital by elevation among the island countries. It has been the country's largest population center since at least the 18th century. The Presidency, National Assembly, Senate, and Supreme Court are located there, as are 21 diplomatic missions and the headquarters of many national and international businesses and non-governmental organizations. It has more universities, nightclubs, art venues, and medical services than any city on the island. Several national and local sports teams, including the championship-winning national rugby team, the Makis, are based here.

Antananarivo was historically the capital of the Merina people, who continue to form the majority of the city's 1,274,225 (2018 census) inhabitants. The surrounding urban areas have a total metropolitan population approaching three million. All eighteen Malagasy ethnic groups, as well as residents of Chinese, Indian, European, and other origins, are represented in the city. It was founded circa 1610, when the Merina King Andrianjaka (1612–1630) expelled the Vazimba inhabitants of the village of Analamanga. Declaring it the site of his capital, Andrianjaka built a rova (fortified royal dwelling) that expanded to become the royal palaces of the Kingdom of Imerina. The city retained the name Analamanga until the reign of King Andriamasinavalona (1675–1710), who renamed it Antananarivo ("City of the Thousand") in honor of Andrianjaka's soldiers.

The city served as the capital of the Kingdom of Imerina until 1710 when Imerina split into four warring quadrants. Antananarivo became the capital of the southern quadrant until 1794, when King Andrianampoinimerina of Ambohimanga captured the province and restored it as the capital of a united Kingdom of Imerina, also bringing neighboring ethnic groups under Merina control. These conquests continued under his son, Radama I, who eventually controlled over two-thirds of the island, leading him to be considered the King of Madagascar by European diplomats. Antananarivo remained the island's capital after Madagascar was colonized by the French in 1897, and after independence in 1960.

The city is now managed by the Commune Urbaine d'Antananarivo (CUA) under the direction of its President of the Special Delegation, Ny Havana Andriamanjato, appointed in March 2014. Limited funds and mismanagement have hampered consecutive CUA efforts to manage overcrowding and traffic, waste management, pollution, security, public water and electricity, and other challenges linked to explosive population growth. Major historic landmarks and attractions in the city include the reconstructed royal palaces and the Andafiavaratra Palace, the tomb of Rainiharo, Tsimbazaza Zoo, Mahamasina Stadium, Lake Anosy, four 19th-century martyr churches, and the Museum of Art and Archaeology.

The English pronunciation of Antananarivo is /ˌæntəˌnænəˈriːvoʊ/ AN-tə-NAN-ə-REE-voh or /ˌɑːntəˌnɑːnəˈriːvoʊ/ AHN-tə-NAH-nə-REE-voh. The Malagasy pronunciation is [antananaˈrivʷ], and the pronunciation of the old French name Tananarive is /təˌnænəˈriːv/ tə-NAN-ə-REEV or /ˌtænənəˈriːv/ TAN-ə-nə-REEV in English and [tananaʁiv] in French.

Antananarivo was originally the site of a town called Analamanga, meaning "Blue Forest" in the Central Highlands dialect of the Malagasy language. Analamanga was established by a community of Vazimba, the island's first occupants. Merina King Andrianjaka, who migrated to the region from the southeast coast, seized the location as the site of his capital city. According to oral history, he deployed a garrison of 1,000 soldiers to successfully capture and guard the site. The hill and its city retained the name Analamanga until the reign of King Andriamasinavalona, who renamed it Antananarivo ("City of the Thousand") in honor of Andrianjaka's soldiers.

Antananarivo was already a major city before the colonial era. After expelling the Vazimba who inhabited the town at the peak of Analamanga hill, Andrianjaka chose the site for his rova (fortified royal compound), which expanded over time to enclose the royal palaces and the tombs of Merina royalty. The city was established in around 1610 or 1625 according to varying accounts. Early Merina kings used fanampoana (statute labor) to construct a massive system of irrigated paddy fields and dikes around the city to provide adequate rice for the growing population. These paddy fields, of which the largest is called the Betsimitatatra, continue to produce rice.

Successive Merina sovereigns ruled over the Kingdom of Imerina from Analamanga through King Andriamasinavalona's reign. This sovereign gave the growing city its current name; he established the Andohalo town square outside the town gate, where all successive sovereigns delivered their royal speeches and announcements to the public, and assigned the names of numerous locations within the city based on the names of similar sites in the nearby village of Antananarivokely. Andriamasinavalona designated specific territories for the hova (commoners) and each andriana (noble) subcaste, both within the neighborhoods of Antananarivo and in the countryside surrounding the capital. These territorial divisions were strictly enforced; members of subcastes were required to live within their designated territories and were not authorized to stay for extended periods in the territories reserved for others. Numerous fady (taboos), including injunctions against the construction of wooden houses by non-nobles and the presence of swine within the city limits, were imposed.