Gangnam District is one of the 25 districts of Seoul, South Korea. The term Gangnam translates to "South of the [Han] River". Gangnam District is the third largest district in Seoul, with an area of 39.5 km2 (15.3 sq mi). As of the 2017 census, Gangnam District had a population of 561,052. There is a high concentration of wealth in the district, with prices for an apartment as of 2020 nearly double those in the rest of Seoul. Gangnam District is part of Gangnam School District Eight, along with the Seocho District. This district shares half of Gangnam-daero Gangnam Station area with Seocho District, which is one of the most crowded places in South Korea.

Gangnam, sometimes referred to as the Greater Gangnam Area, is a geographic and cultural region in Seoul. While Gangnam can refer to the entire region of Seoul south of the Han River, the region is generally defined as consisting of the city's affluent Gangnam, Seocho and Songpa districts. Other definitions define Gangnam by the boundaries of the Gangnam Eighth School District or by the commercial zones around Gangnam Highway, Yangjae Station, Sinsa Station, Nonhyeon Station, Sinnonhyeon Station and Gangnam station. These definitions exclude the Songpa District, which has been argued to be culturally and administratively distinct from the Gangnam and Seocho districts.