A gu (Korean: 구), or district, is an administrative unit in South Korea.

There are two kinds of districts in South Korea.

One is the autonomous district (자치구; jachigu) of special and metropolitan cities, which is a municipal entity similar to a city with its own mayor along with its own legislative council.

The other is the non-autonomous district (일반구; ilbangu) of municipal cities.

Cities with over 500,000 people are allowed to have gu (notable exceptions to this rule are the cities of Gimhae, Hwaseong, and Namyangju).