Kinshasa (; French: [kinʃasa]; Lingala: Kinsásá), formerly named Léopoldville until 30 June 1966, is the capital and largest city of the Democratic Republic of the Congo. Once a site of fishing and trading villages along the Congo River, Kinshasa is now one of the world's fastest-growing megacities. Kinshasa's 2024 population was estimated at 17,032,322. It is the most densely populated city in the DRC, the most populous city in Africa, the world's fourth-most-populous capital city, Africa's third-largest metropolitan area, and the leading economic, political, and cultural center of the DRC. Kinshasa houses several industries, including manufacturing, telecommunications, banking, and entertainment. The city also hosts some of DRC's significant institutional buildings, such as the Palais du Peuple, Palais de la Nation, Court of Cassation, Constitutional Court, Cité de l'Union Africaine, Palais de Marbre, Stade des Martyrs, Immeuble du Gouvernement, Kinshasa Financial Center, and multiple federal departments and agencies.

Covering 9,965 square kilometers, Kinshasa stretches along the southern shores of the Pool Malebo, on the Congo River. It forms an expansive crescent across flat, low-lying terrain at an average altitude of about 300 meters. Situated between latitudes 4° and 5° and longitudes East 15° and 16°32, Kinshasa shares its borders with the Mai-Ndombe Province, Kwilu Province, and Kwango Province to the east; the Congo River delineates its western and northern perimeters, constituting a natural border with the Republic of the Congo; to the south lies the Kongo Central Province. Across the river sits Brazzaville, the smaller capital of the neighboring Republic of the Congo, forming the world's second-closest pair of capital cities despite being separated by a four-kilometer-wide unbridged span of the Congo River.

Kinshasa also functions as one of the 26 provinces of the Democratic Republic of the Congo and is administratively divided into 24 communes, which are further subdivided into 365 neighborhoods. With an expansive administrative region, over 90 percent of the province's land remains rural, while urban growth predominantly occurs on its western side. Kinshasa is the largest nominally Francophone urban area globally, with French being the language of government, education, media, public services and high-end commerce, while Lingala is used as a lingua franca in the street. The city's inhabitants are popularly known as Kinois, with the term "Kinshasans" used in English terminology.

The Kinshasa site has been inhabited by Bantus (Teke, Humbu) for centuries and was known as Nshasa before transforming into a commercial hub during the 19th and 20th centuries. The city was named Léopoldville by Henry Morton Stanley in honor of Leopold II of Belgium. The name was changed to Kinshasa in 1966 during Mobutu Sese Seko's Zairianisation campaign as a tribute to Nshasa village.

The National Museum of the Democratic Republic of the Congo is DRC's most prominent and central museum, housing a collection of art, artifacts, historical objects, and modern work of arts. The College of Advanced Studies in Strategy and Defense is the highest military institution in DRC and Central Africa. The National Pedagogical University is DRC's first pedagogical university and one of Africa's top pedagogical universities. N'Djili International Airport is the largest airport in the Democratic Republic of the Congo and ranks 37th in Africa in terms of passengers carried, with 12 international flights per day. In December 2015, Kinshasa was designated as a City of Music by UNESCO and has been a member of the Creative Cities Network since then. Nsele Valley Park is the largest urban park in Kinshasa, housing a range of fauna and flora. According to the 2016 annual ranking, Kinshasa is Africa's most expensive city for expatriate employees, ahead of close to 200 global locations.